01:02:28
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[00:00:03] Prof. Paul Gissen: Sorry, Still waiting or start? Start, please. Good afternoon, ladies and gentlemen. Today, we have this session 2 of the Early Diagnosis of Metachromatic Leukodystrophy and the topic of the today is Understanding the Diagnostic Journey of Patients presented by Dr. Anna Ardissone today and myself. I'm Paul Gissen and I'm a clinical professor and a consultant in pediatric metabolic diseases at UCL Institute of Child Health and Great Ormond Street Hospital. So, before we go into the presentation, I've got some messages for you. Please don't take any screenshots and do not reproduce any of the slides, content, or images without the permission of the speakers. We are going to have about 50- minute presentation and after that, we'll be very happy to take your questions and we will try to answer as many as we can. Please send your questions by text. We can submit your questions at any point through the questions panel. It really has to be by text and not verbally and the recorded webinar will be available later on on the website that is displayed over here. So, going to my presentation and I'm going to talk about Metachromatic Leukodystrophy or MLD, Understanding the Diagnostic Journey. So, what we would like you to learn today, I would like you to have a good understanding of the clinical and laboratory underlying pathology of Metachromatic Leukodystrophy. I would like you to know which laboratory tests need to be requested in order to get the diagnosis of MLD. I want you to get the point that there are some differences in different subtypes of the MLD and that leads to different progression of this illness. And then, of course, in the session, you will also be able to understand the potential implications of the diagnosis on the clinical management of this disorder. So, just the basic principles of MLD. It's a rare autosomal recessive disorder and the birth prevalence or incidence is 1 in 40, 000 births. That's an average that's estimated and, of course, depending on where you are in some countries, these could be slightly different depending on the ethnic background. This disorder is caused by a mutation in the ARSA gene which encodes lysosomal enzyme arylsulfatase A or ARSA. A very similar phenotype can be caused by mutation in a different gene, PSAP, which encodes prosaposin or also known as activator protein saposin B. And, in addition, the ARSA deficiency can also be caused by mutations in the SUMF1 gene causing multiple sulfatase deficiency. And SUMPF1 mutations could also generate quite a variable phenotype and the reason that ARSA deficiency occurs because, of course, this is the sulfatase and it requires SUMPF1 to function. So you get the deficiency of this enzyme as well. So the resulting pathology of having mutations in ARSA and the abnormal enzyme function is the accumulation of sulfatides in multiple organs. And these organs include the central and peripheral nervous system, but also other visceral organs such as gallbladder, kidneys and the liver. So a bit more on the pathophysiology of MLD ARSA is involved in sulfatide metabolism through hydrolyzing 3- O ester bonds of galactosyl and lactosyl sulfatides and you will see the actual chemical structures in a minute And what happens when you have a deficiency of this enzyme the sulfatides accumulate in the so- called Metachromatic granules. So metachromatic means that they change color And of course, that's how this disease was diagnosed many years ago And these granules accumulate in oligodendrocytes Schwann cells and some of the other cells the accumulation of sulfatides Lead to damage to myelin sheaths and that results in demyelination in both peripheral and central nervous system In addition to that due to this chemical toxicity of sulfatides There is a block in differentiation of precursor cells into oligodendrocytes and that prevents Remyelination. So the damage is that the current myelin sheaths get Annihilated and the new ones don't occur. So the overall you get Demyelination of the in the central and peripheral nervous system So over time you have progressive loss of gross and fine motor functions In addition to that there is a decline in cognitive function eventually leading to premature death in all types of MLD This is a bit more In what it looks like. The Panel on the top shows the neuron and you could see the axons with the surrounding what should be myelin sheaths and as you could see the sulfatides that are present they cause damage to these myelin sheaths and in addition to that there is a problem with remyelinating. So at the bottom panel, you see the actual sulfatides. So you see these sphingolipids which contain the Ceramides the so- called sphingosine base, which has the ceramide and the long chain Fatty acid. This is this long tail that you could see and what you see here is that the sulfatide that should be cut off by the ARSA actually doesn't happen. So these sphingolipids ceramide chemicals are accumulating and causing the damage. So how do we normally diagnose these patients? And these sulfatides can be detected Particularly in the urine they can also be detected in blood and they can be detected in blood spots These methods are becoming more Widespread and available And essentially can be used if necessary If you would like to screen for this condition, but of course, it's not necessary if you want a faster Detection. So the diagnosis is made using a combination of an enzyme assay and mutation analysis It is quite important to do the mutation analysis because of several reasons So one is that the pseudodeficiency exists. So when you have abnormal enzymatic result you need to be sure that this is not because of pseudodeficiency. But in fact it's due to the true deficiency of the ARSA. In addition as I said multiple sulfatase deficiency can also give you abnormal enzyme results so you need to exclude that too. And then mutation, of course, where would you go with that? There are specific mutations that are known to be associated with Pseudodeficiency, and you can screen for them both in the patients and in the family. And, of course, you can do the carrier testing once you've detected the pathogenic mutation. So the next few slides, I wanted to demonstrate that there are several subtypes of MLD. Some of them are early onset, and these are the late infantile phenotype and early juvenile. So first of all, late infantile is the kids who present below the age of two and a half. This phenotype typically starts with motor abnormalities. The patients have loss of milestones, ataxia, muscle weakness, polyneuropathy, and then there is a progressive loss of motor and cognitive functions. And the life expectancy is typically less than 10 years. The other early presenting phenotype of MLD is early juvenile. And these patients present between the age of two and a half and six years. This is more of a mixed motor and cognitive abnormalities, although the initial noticeable features are still probably more likely to be motor, with a progressive loss of both motor and cognitive function. And again, the life expectancy typically is less than 10, although some patients can live quite a bit longer. Then the later presenting phenotypes are the late juvenile and then the adult phenotype. So the late juvenile phenotype of MLD present between the ages of six and 16. And this is definitely a mixed, sort of at the same time, they present with motor as well as cognitive abnormalities. And then the loss of the skills is over a longer period of time and may take longer than 10 years from presentation before these patients die. Then finally, the adult phenotype MLD. These patients present after the age of 16 and can be quite a bit later. This is predominantly a cognitive presentation with behavioral changes, learning difficulties and psychiatric problems. But of course, over the following many years, they have both the cognitive and motor deterioration. And the patients can live a few tens of years after the diagnosis. But eventually, of course, they still have a very shortened life expectancy. In terms of the brain MRI and MLD, the typical presenting features would be the deep white matter disease, with sparing of the subcortical white matter and without the leading edge of enhancement. What you see here is features on the T2 flare and T1 with the gadolinium MRI scans. However, the MRIs can be normal in early disease, particularly in the late infantile form before the patients start progressing. And then at the later stages, what you see is so-called tigroid or leopard skin appearance due to perivascular space distension and other sites of involvement. You could see in the corpus callosum, internal capsules, corticospinal tracts and cerebellar white matter. In the next few slides, I'm going to present three cases, briefly, of the patients, of my own patients, that with different types of MLD. So, the first patient was a boy, he was in very good general health, and was performing at a very high level academically, in a very selective school, with patients with excellent academic abilities. He was also playing music, but at the age of 12, he started struggling with academic performance, and at the same time, started getting clumsier. His handwriting became more difficult to understand, he started struggling playing saxophone and football that he loved. It took quite a while for him to get to the diagnosis, because of the level that he started was really high. Eventually, he got to the neurologist, and by then, the MRI scan appearance was typical. He had the enzyme assay and mutation analysis that confirmed the diagnosis of MLD, so he was late juvenile form MLD. At the time of early investigations and early assessments, he had normal physiotherapy assessment, and his EMG and nerve conduction was normal. He was referred for bone marrow transplant, which he did get at the age of 13 and a half. At the time, his verbal comprehension index was 95 still. He had reasonable perceptual reasoning and working memory. His processing speed was already significantly delayed. He did undergo allogeneic bone marrow transplant, and in the follow-up years, he had progressive spasticity. He was functioning at pretty low cognitive level and couldn't really maintain school attendance. At the age of 18, he was still able to walk with support, despite the severe spasticity. He could still communicate in short sentences. Sadly, two years after transplant, he developed Ewing sarcoma and then eventually died at the age of 20 due to the complications of bone sarcoma. My next case is a young lady who had a normal perinatal history. She had normal early development, but noted to be a bit wobbly on her legs at the age of two and a half, so sort of on the edge between the late infantile and early juvenile age. At the age of three, she had clearly noticeable worsening of motor condition, and she was frustrated of not being able to do things. She developed strabismus and some difficulty with expressive speech. Nevertheless, she was well enough not to be investigated by a neurologist. She had further difficulties with fine motor skills, for example, taking lid off her pen and doing up the zip at the age of three and a half, and had developed frequent falls. She started school at the age of four and then noticed gross and fine motor problems, balance and coordination, and physiotherapy started with some success, improving her skills. At the age of five, her tremor was noted, and she developed hyperacusis. At the age of five and a half, she actually went for full investigations by then, and MRI showed poor myelination, suggesting MLD, and she was then investigated, eventually diagnosed with MLD at the age of six on the basis of enzymology and genetics. And at the time, she had mild hypotonia, poor reflexes, normal power, and slightly abnormal balance. At the age of seven, she received ex vivo gene therapy, and now she's 15, eight years post-transplant. She communicates in complete sentences, but she has reduced performance for her age. She has no locomotion, meaning she's not really initiating movements, and she's not able to sit without support, but has some head control. Finally, my third case is again a young lady who is generally healthy and normal development until the age of five, but at the age of five she became unsteady on her feet and behavior became immature. She developed poor attention and at the time had an MRI which described leukodystrophy consistent with MLD. She had ataxia, but normal power and tone and some coordination problems. She did not unfortunately qualify for the gene therapy and wasn't treated specifically. Now at the age of 18, she has no expressive language, no voluntary movements. She had severe spasticity and additional problems are sleep apnea, epilepsy, inflammatory bowel disease. She only fed via gastrostomy and is wheelchair dependent. She has also a neuropathic bladder. So all this emphasizes that really there is a difficulty in diagnosing these patients quickly enough and what are my initial thoughts really of how can we achieve early diagnosis? Well newborn screening would be obvious of course because that eliminates the difficulty with picking up these early signs and anyway when the patients have early signs it's already too late to try and diagnose them because the treatment should probably be instigated before any symptoms start. And there are already pilot newborn screening projects running in the US and Australia and there is a generation study in the UK where patients are being screened by whole genome sequencing. Providing better knowledge of disease presentation of course hopefully will achieve the result of some patients being diagnosed earlier and using the diagnostic tests early of course helps with providing the diagnosis earlier. There are challenges with newborn screening because the genetics may not be able to predict the phenotype and neither could the diagnostic tests when there is no obvious genotype-phenotype correlation. And the availability of treatment is variable depending on where you are located.
[00:23:22] Prof. Paul Gissen: So here I finish my initial presentation and happy to go for some initial discussion I think Anna.
[00:23:30] Prof. Paul Gissen: Okay, thanks Paul for your very interesting presentation and to underline the importance and the difficulty to early diagnosis in this kind of disorder. I have two questions, one from a clinical point of view, based on your experience and your opinion, which kind of medical specialist, I mean child neurologist, pediatrician, more frequently evaluate this patient at clinical onset and so which one should be teaching about MLD?
[00:24:13] Prof. Paul Gissen: So I think it depends a little bit on which country you are in. So for example, I know about the UK better. So these patients get first seen by the community pediatricians and then probably general pediatricians. And if they have very soft signs, then they would not be directly referred to a neurology opinion. So I think it's really important for general pediatricians and community neurodevelopmental pediatrician to appreciate the importance of early diagnosis because I think by the time they get to a neurologist who is used to seeing rare disorders and knows about potential for having the white matter or gray matter disorders. So it's very much likely that by the time they get to a neurologist, of course the neurologist is going to initiate the diagnosis. Our problem is that by the time they get to a neurologist, that precious time for early diagnosis is lost. So I think it's important for, first of all, for us, of course, the neurologists need to know, but in my experience, they do know. It's the people who don't know are those that are not used to seeing these rare disease patients. And I think that's that's really the point.
[00:25:52] Dr Anna Ardissone: Yeah, yes, I agree. It's quite similar in Italy, for example. OK, and the second question about the diagnostic tools, how often is the diagnosis achieved by NGS panel on leukodystrophy or genetic neuropathy in spite of specific biochemical study for MLD in your experience?
[00:26:19] Prof. Paul Gissen: Well, when the signs are very nonspecific, it is possible that the whole genome sequencing is done. I mean, the issue here, the issue with doing the sort of nonspecific test is that when it is sent as non-urgent, then potentially the wait here could easily be six months. So I think that is a real danger as thinking, oh, there is a nonspecific presentation, we don't know what, so I might as well just send the whole genome sequencing and then it will come back. By the time it comes back, again, the precious time is going to be lost and we'll get a patient who has deteriorated very significantly. So it might still happen. I mean, I have not seen it recently, but it might still happen. But it would be a big loss if we wait and don't do the specific tests.
[00:27:28] Dr Anna Ardissone: Yes. It's a problem because it leads to a diagnostic delay very often. Exactly. Exactly. Thank you, Paul.
[00:27:38] Prof. Paul Gissen: Thank you.
[00:27:41] Dr Anna Ardissone: Okay. So I can go on. Now, I'm Anna Ardissone. I'm a child neurologist my area of interests are neurodegenerative and neurometabolic disorders including leukodystrophy. So some information are overlapping with the previous presentation but I think it is important to underline and to stress the topic of this area. I start briefly summarizing the topic of the disease disorders we are talking about which are rare and fatal neurodegenerative disorders caused by enzyme deficiency resulting in an internalized osmosis accumulation of supatite, leading to a progressive demyelination and neurodegeneration. We know three clinical subtypes, as Paul said before, based on age at onset, late infantile, juvenile, and adult. The different are also related to the different clinical symptoms and the clinical picture during the course of the disease. A common finding is the severe and progressive motor and cognitive manifestation, leading to a very severe picture in the late stage of disease, with dysphagia, vegetative state, and premature death. The diagnosis, as we see before, can be challenging and is often delayed or missed, and this is a problem because of the treatment. Treatment available today is gene therapy or hematopoietic stem cell transplantation, but also in selected cases. So, in asymptomatic disease more often the management is unsupported and has limited efficiency in delaying disease progression. So in this context the importance of early diagnosis is related to these three points the fatal, neurodegenerative nature of the disease, the delayed diagnosis and the possibility of treatment in only selected cases. Few words about the possible, the available treatments in this disorder. Gene therapy has shown to modify the natural history of metachromatic leukodystrophy, but indications are limited in two conditions. The first, in children with late infantile or early juvenile forms are symptomatic, but in a very early stage of the disease, and so when the present ability to work independently and IQ is over 85, that means before the onset of cognitive decline. Some times it is possible stem cell transplantation, but only in juvenile forms and if performed in a very early stage of disease. In these cases, it can delay the progression of the disorders and this treatment is not indicated in late infantile cases. So the issue is an early diagnosis in order to treat this patient and this fatal condition. I want to underline this aspect in sharing clinical cases, my own clinical cases in the common clinical. Today, there was a problem with my internet on my office. So we are talking, I'm saying that I want to share some clinical cases which underline this difficulty to perform early diagnosis. Please go OK. The first is a patient with personally history unremarkable and also family history even if the parents report a younger sister with school, unspecified school difficulties who is undergoing specific evaluation concurrently to the patient's first evaluation. The medical history of this patient started at six years of age because of school difficulties beginning in the first grade. So a neurological evaluation was performed and was normal. A cognitive assessment disclosed IQ of 62 and so the child was supplied with educational aid and started speech therapy. But in the following years, there was a gradual worsening with increased difficulties in understanding and performing tasks and decreased motor coordination. The parents reported difficulties walking, running, going downstairs, and easy fatigability. So the patient was first evaluated at our institution at nine years and eight months of age. At neurological examination, the child showed a good understanding of simple commands but occasionally delayed and as we are often consistent with the context sometimes repetitive and presented also echolalia and stereotypes. Neurological motor evaluation disclosed increased tension in the tibiotarsal joint, tremor, dysmetria, ataxic gait, and lower girdle weakness. So summarizing, the clinical picture of this patient is a positive family history for unspecified cognitive difficulties, a symptom- free interval, and then cognitive deterioration from age six. Then the presence of cerebellar and mild pyramidal signs and a progressive worsening in time. So rapidly, the patient underwent an MRI, which disclosed the typical metachromatic MRI pattern. And the white matter involvement was confirmed by neurophysiological exams. Moreover, ENG disclosed a pattern suggested for sensorimotor demyelinating neuropathy. Of course, metachromatic leukodystrophy was suspected and it was confirmed by enzymatic assay and sequencing of ARSA gene. And so a diagnosis of metachromatic leukodystrophy early juvenile forms was achieved. Rapidly, the patient's sister was evaluated. The medical history is quite similar to patient one, symptom- free interval and then school difficulties from 6 years of age. Because of this the patient was evaluated and a cognitive assessment revealed IQ of 79 and the profile showed discrepant scores between indexes. An assessment for a possible learning disability was completed and the overall performance is significantly impaired in reading, writing, logical, mathematical skills, as well in attention and acceptance function. So a personalized education plan and speech therapy was started, but non- instrumental exams were performed.
[00:36:23] Prof. Paul Gissen: After her brother's evaluation, the patient came to our attention. The neurological examination showed easy distractibility and occasional difficulty following instruction. A positive Babinski sign, bilateral clumsiness in the adiadochokinesia test and during the tandem walk. Unfortunately, the MRI disclosed a very important white matter involvement in according to the familial diagnosis. And so the familial mutation where the search and the diagnosis of metachromatic leukodystrophy early juvenile, as in her brother, was achieved in a symptomatic phase. The last case is a very little child with a family and personal history unremarkable. Even if the motor development was further normal but the first steps are reported at 15 months of age. So maybe a mild motor delay was suspected in a retrospective way. The real medical history started at 17 months of age. The parent reported a broad- based gait with high guard posture and instability of the lower limbs. The patient underwent orthopedic assessment that was normal and a neurological evaluation was recommended. At 21 months, the patient worsening because the gait becomes unstable and was associated with frequent falls. And the child refers frequent pain at lower limbs. So neurological evaluation. The first neurological evaluation was performed at 21 months of age and revealed the generalized hypotonia and the absence of reflexes in the lower limbs and a wide- based gait with the bilateral knee hyperextension. Brain MRI was performed that was referred normal. ENG study revealed the demyelinating sensorimotor neuropathy andin all four limbs. So genetic neuropathy was suspected and NGS gene panel with genes related to neuropathy is initiated. But waiting for this result, the patient presented additional symptoms at 22 months of age. The child became unable to hold an egg. Her parents referred tremor when manipulating objects and choking while drinking. So probably an initial dysphagia. The patient was re- evaluated in the same center and the examination revealed additional signs in terms of Babinski and ataxic gait. So summarizing the clinical picture of this patient is a symptom-free interval and when the decline of motor abilities from 17 months of age, a peripheral demyelinating neuropathy, and then the presence of cerebellar and pyramidal signs. So in the meantime, the result of NGS panel were available and disclosed the presence of two variants in ARSA gene confirmed by enzymatic assay. And so metachromatic leukodystrophy diagnosis as a late infantile form was achieved in this patient. When the patient arrived at our institution for evaluation about possible treatment is late for any kind of treatment. In all these three cases, there is a diagnostic delay from the first symptom to diagnosis in yellow, the first neurological evaluation, and a diagnostic delay from three, four years to nine months in the third cases. Which are the consequences of this diagnostic delay? The first patient was not eligible for any kind of treatment, not for gene therapy, not for hematopoietic stem cell transplantation. His sister was unfortunately diagnosed in an asymptomatic phase, so she was not eligible for gene therapy and she underwent hematopoietic stem cell transplantation. And the last patient was not eligible for any kind of treatment. So, looking at these cases that are quite similar to Paul's one, it is very clear the importance of an early diagnosis of these disorders in order to treat this fatal neurodegenerative condition. It not only important but necessary and early diagnosis of these patients. And the scenario is very different in these three different conditions. In symptomatic patients, in their early stage of disease, it is different in presymptomatic patients, in this case, and different also in presymptomatic patients without known positive family history. So, starting from this experience, how is it possible to improve diagnosis? Starting from symptomatic patients, which is the topic of the diagnostic flowchart in this condition? First, the clinical instrumental suspicion, then biochemical markers, analysis, and finally gene-specific sequencing. Summarizing the clinical instrumental suspicion, it's quite similar in the three different forms. It is characterized by a symptom-free interval, then motor and cognitive involvement, in terms of psychomotor delay, motor incoordination, cognitive or behavioral difficulties, and signs of motor involvement. Then, MRI, which discloses the white matter involvement with a specific pattern, and involvement on deep white matter and sparing subcortical white matter, and in the last stage, tigroid pattern, confirmed by abnormal condition and potential, and demyelinating It is important also to underline the possibility to a gallbladder alteration disclosed by abdominal ultrasound. In this condition, in symptomatic patients, based on this point, is it possible to do, to perform biochemical- specific analysis. arylsulfatase dosage, leukocytes and DBS, associated to elevated sulfatides in urine, serum, and DBS. And then, when biochemical study confirmed clinical suspicion specific genetic test disclosed a mutation in ARSA gene and confirmed diagnosis. But in the common clinical practice it is possible unfortunately that in initial phases of nonspecific condition the right pattern of leukodystrophy leads to start with NGS panel of genes related to leukodystrophy, or, as we've seen in the third case, the presence of demyelinating neuropathy leads to NGS panel with genes related to neuropathies or WES. But as we have discussed before it is very dangerous because it leads to a diagnostic delay. Diagnostic delay, that is very common, this is very common. The experience of my own cases is confirmed by experience in the literature data, both in late infantile and early juvenile form it is reported a significant diagnostic delay from two to three, four years, according to experience of our cases. So it's a very common problem. So looking at the challenges in early diagnosis in symptomatic patient. The first are related first types are related to clinical presentation and the clinical evaluation because the symptoms are quite uncommon, quite unspecific, and can be confused with other neurological disease, also non- progressive disease, also untreatable or treatable disease. So very different scenario.
[00:46:51] Prof. Paul Gissen: Moreover, the more suggestive clinical radiological pictures are present after irreversible neurological damage has occured so very late in the story or the medical history of the patient. It is important also the lack of awareness among healthcare providers. Due to the relative or metachromatic laparoscopy, healthcare providers may not be familiar with each symptom, and so it's not possible to have a correct clinical suspicion in a very early stage of the disease. And finally, the access to diagnostic tools is not the same in each country and in each region in the same country, because of high costs or limited access to genetic testing. So this is, in my opinion, the main problem of early diagnosis in symptomatic patients. Thinking about this, what we can do better? The first is clinical management. Our cases showed the very importance to pay attention to personal and familiar history of the patient. To pay attention to cognitive profile, because cognitive impairment is very common in child neurology, but it's very different, a cognitive decline and a cognitive delay, which is common in non- progressive condition. Third, pay attention to instrumental exams because MRI, when MRI discloses a liquid dystrophy pattern, also known as pathognomonic of MLD or other one, generally, the more common forms for the patient age should be really the health first. First of all, the treatable condition, including MLD, Krabbe disease, adrenoleukodystrophy, which of course, different MRI pattern, but it's important to exclude, first of all, treatable condition before it's late. And thinking about metachromatic leukodystrophy it is important an abdominal ultrasound because it may reveal pathognomonic gallbladder alteration . On the other hand, MRI, non- normal MRI doesn't exclude metachromatic leukodystrophy, because as conventional MRI may appear normal in the pre- symptomatic stage, as the third case showed before. And, thinking of the third case, metachromatic liquid dystrophy should be suspected also in apparently isolated demyelinating neurons. Thinking about biochemical and diagnostic tools, in suspected metachromatic, the biochemical study is the most rapid test to identify affected individuals, and then it should be confirmed by genetic test. And as Paul said before, during our discussion, the NGS panel for liquid dystrophy or neuropathies, it's very dangerous because may delay diagnosis. Moreover, it's very important to improve knowledge with the different healthcare providers, as we are doing now, because knowing is important to be able to diagnose. And third, when there is a suspicion of this kind of disorders, it is very important to direct the patient to a reference center, both for diagnostic workup and treatment option. Just a few words about the other two conditions. In the pre- symptomatic patient, siblings of index cases and asymptomatic patient without family history. Of course, in this case, the diagnostic workup is very different. In seamless or off- index case, they should be tested for MLD, even if asymptomatic. And then the quickest way to confirm or exclude MLD is concurrently perform enzyme activity and gene testing, and then perform instrumental tests. These studies should be reserved for confirmed case, but it's important to confirm or exclude the MLD in a brief time. Different, of course, is the early diagnosis in pre-symptomatic with a known positive family history, so in newborn, and so I mean in newborn screening, it allows to diagnose the MLD in the natal period, but it is a growing approach in a lot of countries, but the problem is that the genetic diagnosis is not related to phenotype, and so it is important to monitor the patient, but to identify the moment to treat the patient. So, I think I have concluded my presentation.
[00:52:31] Prof. Paul Gissen: Thank you very much. That was a great presentation. I think, I don't know if we have, I have a couple of questions to ask maybe and then we have the other questions potentially. So and I wondered what are the challenges with starting newborn screening? The reason of course is that yes it's great to diagnose patients as early as possible but that if we have early diagnosis of early juvenile patients that we can still treat them with gene therapy of course really early. But with the late infantile we can try very hard but really we need to diagnose patients pre-symptomatically in order to be able to treat them, which means that we need to have newborn screening in order to diagnose new patients unless they have a sibling. So what are the particular challenges, if you see any challenges, to having newborn screening in Italy?
[00:53:43] Dr Anna Ardissone: The problem with newborn screening is that we can achieve a diagnosis of a degenerative disorders but we are not able to predict the phenotype and so the possibility to identify a possible treatable form of MLD. And so in Italy we have the possibility to newborn screening only in one region. Now it's very recent in also in other regions so we are learning from this experience but I think that this condition is very different from, for example, newborn screening for x-ALD, in which we know a different phenotype but we know that it is important to monitor the patient, to direct the patient to a treatment if it shows signs of cerebral harm. In MLD it's very different because we don't know if the patient will show a treatable form of MLD or a non- treatable form. So I think it's a challenge common with other countries and I don't know which should be the solution.
[00:55:09] Prof. Paul Gissen: Yeah, it's difficult to predict some, of course, some mutations, maybe there is some genotype-phenotype correlation so you can potentially predict that. So it's not that.
[00:55:25] Dr Anna Ardissone: Maybe we have to study, moreover, this kind of disorders about the other epigenetic factors, other factors that can modify and give information about phenotype-genotype correlation. I don't know.
[00:55:42] Prof. Paul Gissen: Yes, yes, would be good to know. So would you say that this is the main challenge? So do you see newborn screening coming in, you know, in the whole of Italy, in MLD?
[00:55:56] Dr Anna Ardissone: Not in all Italy, now only in two of 20 regions, but they are pilot studies.
[00:56:05] Prof. Paul Gissen: But is that, okay, so hopefully it's a start and maybe that will expand.
[00:56:11] Dr Anna Ardissone: Yes, maybe.
[00:56:12] Prof. Paul Gissen: Okay, we've only got a few minutes. Do we have any questions from the audience? There we go. So somebody is asking whether the case I presented of the late juvenile patient who developed Ewing sarcoma and the question is whether that's more common in MLD. It's not that I'm aware that that is the case. There are certain things that are more common in MLD and that's particularly the gallbladder tumors. That's been described at increased incidence as well as the gallstones in MLD, but not bone tumors. There is, it's a possibility that because it may be associated with the chemotherapy that the patient had to have for bone marrow transplant, that that may have something to do with that. But not, I don't think it's MLD specific. I don't know if you've heard anything like that, Anna.
[00:57:25] Dr Anna Ardissone: No, my experience no, not related to MLD and also not related to hematopoietic stem cell transplantation.
[00:57:34] Prof. Paul Gissen: Okay.
[00:57:35] Prof. Paul Gissen: Never, in other condition also, never.
[00:57:38] Prof. Paul Gissen: Maybe just very unfortunate and that's why he developed it. That was a very sad case. Okay, we'll have another patient. Okay. Patient.
[00:57:50] Dr Anna Ardissone: Yes.
[00:57:52] Prof. Paul Gissen: Yeah. I think it's for you.
[00:57:55] Dr Anna Ardissone: Yes. But these signs that are suggested for neuropathy and cerebellar involvement in this patient are common in early, in infantile form, but in advanced stage of disease. Not, is not common in the common clinical practice of child neurology. Others suspect that were not present? No, no others.
[00:58:35] Prof. Paul Gissen: So maybe if you repeat the question, because I think the others may not answer the question.
[00:58:42] Prof. Paul Gissen: Yes.
[00:58:48] Prof. Paul Gissen: Okay. Do we have any other questions? Here's another one. Six month wait for non-specific sequence was a surprise. I think that's what he said.
[00:59:10] Dr Anna Ardissone: If his comment is related to patient three, I suppose, I agree that was not good critical practice and I share this case just to underline the dangers of non- specific NGS panel analysis. Not six or nine months, but worse. But I agree that is important to prioritize the specific test when there is a possible treatable condition of MLD and other. And was the reason why I want to share this case with you to underline the justice point.
[00:59:54] Prof. Paul Gissen: But it's not, I agree. So actually in, in, in our, not in my own practice, but I think generally in the UK, they await the waiting time to get the genetic results back. Unless you ask for it specifically to be done urgently, it could easily take longer than six months. And of course you see a patient, you, you, you detect in some signs, you've sent the genetic, well, a doctor sent the genetics away. And then you say, okay, I'll see you again in six months. And if you don't, you don't know that in these six months, there is an evolution of disease, significant evolution, and the parents may not be raising any issues. They may be at home. So then six months later you get it and it's, you know, the patient cannot be treated anymore. So it definitely is possible. So the good old enzyme analysis is still, is still important. It's still important. What resources and support are available to help families navigate the diagnosis of MLD in their child? Anna, in your, in your case?
[01:01:14] Dr Anna Ardissone: In my case, there aren't any kind, kinds of support for the parents, unfortunately.
[01:01:23] Prof. Paul Gissen: So in the UK, we have patient associations, a couple of patient associations, and we would certainly be able to, so from that point of view, that's very helpful, that we would be able to direct the parents towards these patient family associations and they would be able to get information on the disease. But of course, with these rare, really rare disorders, it's difficult to get specific information sort of availability. Nowadays, of course, they're all able to go to the internet and they can do all of that. Okay, we're running out of time.
[01:02:08] Prof. Paul Gissen: Thank you very much. Thank you. This is the end of session. And thank you, Anna. Thank you, Paul, everyone. Bye. Okay.