Misfolding of fukutin-related protein (FKRP) variants in congenital and limb girdle muscular dystrophies.

Fukutin-related protein (FKRP, MIM ID 606596) variants cause a range of muscular dystrophies associated with hypo-glycosylation of the matrix receptor, α-dystroglycan. These disorders are almost exclusively caused by homozygous or compound heterozygous missense variants in the FKRP gene that encodes a ribitol phosphotransferase. To understand how seemingly diverse FKRP missense mutations may contribute to disease, we examined the synthesis, intracellular dynamics, and structural consequences of a panel of missense mutations that encompass the disease spectrum. Under non-reducing electrophoresis conditions, wild type FKRP appears to be monomeric whereas disease-causing FKRP mutants migrate as high molecular weight, disulfide-bonded aggregates. These results were recapitulated using cysteine-scanning mutagenesis suggesting that abnormal disulfide bonding may perturb FKRP folding. Using fluorescence recovery after photobleaching, we found that the intracellular mobility of most FKRP mutants in ATP-depleted cells is dramatically reduced but can, in most cases, be rescued with reducing agents. Mass spectrometry showed that wild type and mutant FKRP differentially associate with several endoplasmic reticulum (ER)-resident chaperones. Finally, structural modelling revealed that disease-associated FKRP missense variants affected the local environment of the protein in small but significant ways. These data demonstrate that protein misfolding contributes to the molecular pathophysiology of FKRP-deficient muscular dystrophies and suggest that molecules that rescue this folding defect could be used to treat these disorders.

Correlation of GAA Genotype and Acid-α-Glucosidase Enzyme Activity in Hungarian Patients with Pompe Disease.

Pompe disease is caused by the accumulation of glycogen in the lysosomes due to a deficiency of the lysosomal acid-α-glucosidase (GAA) enzyme. Depending on residual enzyme activity, the disease manifests two distinct phenotypes. In this study, we assess an enzymatic and genetic analysis of Hungarian patients with Pompe disease. Twenty-four patients diagnosed with Pompe disease were included. Enzyme activity of acid-α-glucosidase was measured by mass spectrometry. Sanger sequencing and an MLPA of the GAA gene were performed in all patients. Twenty (83.33%) patients were classified as having late-onset Pompe disease and four (16.66%) had infantile-onset Pompe disease. Fifteen different pathogenic GAA variants were detected. The most common finding was the c.-32-13 T > G splice site alteration. Comparing the α-glucosidase enzyme activity of homozygous cases to the compound heterozygous cases of the c.-32-13 T > G disease-causing variant, the mean GAA activity in homozygous cases was significantly higher. The lowest enzyme activity was found in cases where the c.-32-13 T > G variant was not present. The localization of the identified sequence variations in regions encoding the crucial protein domains of GAA correlates with severe effects on enzyme activity. A better understanding of the impact of pathogenic gene variations may help earlier initiation of enzyme replacement therapy (ERT) if subtle symptoms occur. Further information on the effect of GAA gene variation on the efficacy of treatment and the extent of immune response to ERT would be of importance for optimal disease management and designing effective treatment plans.

Ethnicity-related DMD Genotype Landscapes in European and Non-European Countries.

OBJECTIVE: Genetic diagnosis and mutation identification are now compulsory for Duchenne (DMD) and Becker muscular dystrophies (BMD), which are due to dystrophin (DMD) gene mutations, either for disease prevention or personalized therapies. To evaluate the ethnic-related genetic assortments of DMD mutations, which may impact on DMD genetic diagnosis pipelines, we studied 328 patients with DMD and BMD from non-European countries. METHODS: We performed a full DMD mutation detection in 328 patients from 10 Eastern European countries (Poland, Hungary, Lithuania, Romania, Serbia, Croatia, Bosnia, Bulgaria, Ukraine, and Russia) and 2 non-European countries (Cyprus and Algeria). We used both conventional methods (multiplex ligation-dependent probe amplification [MLPA] followed by gene-specific sequencing) and whole-exome sequencing (WES) as a pivotal study ran in 28 patients where DMD mutations were already identified by standard techniques. WES output was also interrogated for DMD gene modifiers. RESULTS: We identified DMD gene mutations in 222 male patients. We identified a remarkable allele heterogeneity among different populations with a mutation landscape often country specific. We also showed that WES is effective for picking up all DMD deletions and small mutations and its adoption could allow a detection rate close to 90% of all occurring mutations. Gene modifiers haplotypes were identified with some ethnic-specific configurations. CONCLUSIONS: Our data provide unreported mutation landscapes in different countries, suggesting that ethnicity may orient genetic diagnosis flowchart, which can be adjusted depending on the mutation type frequency, with impact in drug eligibility.

Expanding the clinical and molecular spectrum of ATP6V1A related metabolic cutis laxa.

Several inborn errors of metabolism show cutis laxa as a highly recognizable feature. One group of these metabolic cutis laxa conditions is autosomal recessive cutis laxa type 2 caused by defects in v-ATPase components or the mitochondrial proline cycle. Besides cutis laxa, muscular hypotonia and cardiac abnormalities are hallmarks of autosomal recessive cutis laxa type 2D (ARCL2D) due to pathogenic variants in ATP6V1A encoding subunit A of the v-ATPase. Here, we report on three affected individuals from two families with ARCL2D in whom we performed whole exome and Sanger sequencing. We performed functional studies in fibroblasts from one individual, summarized all known probands' clinical, molecular, and biochemical features and compared them, also to other metabolic forms of cutis laxa. We identified novel missense and the first nonsense variant strongly affecting ATP6V1A expression. All six ARCL2D affected individuals show equally severe cutis laxa and dysmorphism at birth. While for one no information was available, two died in infancy and three are now adolescents with mild or absent intellectual disability. Muscular weakness, ptosis, contractures, and elevated muscle enzymes indicated a persistent myopathy. In cellular studies, a fragmented Golgi compartment, a delayed Brefeldin A-induced retrograde transport and glycosylation abnormalities were present in fibroblasts from two individuals. This is the second and confirmatory report on pathogenic variants in ATP6V1A as the cause of this extremely rare condition and the first to describe a nonsense allele. Our data highlight the tremendous clinical variability of ATP6V1A related phenotypes even within the same family.

Efficacy of nusinersen in type 1, 2 and 3 spinal muscular atrophy: Real world data from Hungarian patients.

INTRODUCTION: Spinal muscular atrophy (SMA) is an autosomal recessive disorder caused by a homozygous deletion of the survival motor neuron (SMN) 1 gene. Nusinersen is an antisense oligonucleotide enhancing the production of the SMN protein. It has received approval by the European Medicines Agency (EMA) in 2017, based on the clinical trials demonstrating the effectiveness of nusinersen in several types of SMA. In Hungary, the first patient received nusinersen treatment in April 2018. Our aim is to summarize our experience regarding the efficacy, safety and tolerability of nusinersen in our patients. METHODS: Data were collected retrospectively in all types of SMA patients (type 1-3) starting treatment with nusinersen in Hungary between April 2018 and December 2019. Motor functions were evaluated at baseline, at the fourth and all following injections. RESULTS: By 31st December 2019, nusinersen therapy was initiated in 54 patients at either of the two Hungarian treatment centres. Mean age of the patients at the start of the treatment was 6.3 years (±5,4 range 0.4-17.9). 13 patients are type 1 (mean 0.78 ± 0.27, range 0.4-1.5 yrs), 21 patients are type 2 (mean 4.5 ± 3.3, range 1.3-12 yrs), 23 patients are type 3 (mean 10.9 ± 5.2, range 2.9-17.9 yrs). Fourteen patients had severe scoliosis, four of them underwent spine stabilizing surgery. During the study period 340 injections were administered without any new safety concerns emerging. The data of 38 patients, who had completed the first six treatments, were included in the final statistical analysis. Motor function has improved in most of the children. By the 307th day visit, on average, a 14.9 (±5,1) point improvement was measured on the CHOP INTEND scale in type 1 patients (p = 0.016). All patients with type 1 SMA who performed the motor evaluation (7/10) have improved by more than four (7-21) points. Regarding type 2 patients, a 7.2 (range -2- 17) point increase from baseline (p < 0.001) on the Hammersmith Functional Motor Scale Expanded (HFMSE) and 4.3 (range: 2-9) point increase (p = 0.031) on the Revised Upper Limb Module (RULM) were found. The distance of the 6 min walk test also increased by 33.9 m on average (range -16 - 106), in type 3 patients. CONCLUSION: According to our results nusinersen has the same safety and tolerability profile as in the clinical trials. In a heterogenic patient population of SMA type 1 and 2, nusinersen showed similar efficacy as seen in the pivotal studies. A clinically and statistically significant improvement of motor functions was also detectable in type 3 patients with heterogeneous age distribution.

Clinical Outcomes in Duchenne Muscular Dystrophy: A Study of 5345 Patients from the TREAT-NMD DMD Global Database.

BACKGROUND: Recent short-term clinical trials in patients with Duchenne Muscular Dystrophy (DMD) have indicated greater disease variability in terms of progression than expected. In addition, as average life-expectancy increases, reliable data is required on clinical progression in the older DMD population. OBJECTIVE: To determine the effects of corticosteroids on major clinical outcomes of DMD in a large multinational cohort of genetically confirmed DMD patients. METHODS: In this cross-sectional study we analysed clinical data from 5345 genetically confirmed DMD patients from 31 countries held within the TREAT-NMD global DMD database. For analysis patients were categorised by corticosteroid background and further stratified by age. RESULTS: Loss of ambulation in non-steroid treated patients was 10 years and in corticosteroid treated patients 13 years old (p = 0.0001). Corticosteroid treated patients were less likely to need scoliosis surgery (p < 0.001) or ventilatory support (p < 0.001) and there was a mild cardioprotective effect of corticosteroids in the patient population aged 20 years and older (p = 0.0035). Patients with a single deletion of exon 45 showed an increased survival in contrast to other single exon deletions. CONCLUSIONS: This study provides data on clinical outcomes of DMD across many healthcare settings and including a sizeable cohort of older patients. Our data confirm the benefits of corticosteroid treatment on ambulation, need for scoliosis surgery, ventilation and, to a lesser extent, cardiomyopathy. This study underlines the importance of data collection via patient registries and the critical role of multi-centre collaboration in the rare disease field.

European Cross-Sectional Survey of Current Care Practices for Duchenne Muscular Dystrophy Reveals Regional and Age-Dependent Differences.

BACKGROUND: Publication of comprehensive clinical care guidelines for Duchenne muscular dystrophy (DMD) in 2010 was a milestone for DMD patient management. Our CARE-NMD survey investigates the neuromuscular, medical, and psychosocial care of DMD patients in Europe, and compares it to the guidelines. METHODS: A cross-sectional survey of 1677 patients contacted via the TREAT-NMD patient registries was conducted using self-report questionnaires in seven European countries. RESULTS: Survey respondents were 861 children and 201 adults. Data describe a European DMD population with mean age of 13.0 years (range 0.8-46.2) of whom 53% had lost ambulation (at 10.3 years of age, median). Corticosteroid medication raised the median age for ambulatory loss from 10.1 years in patients never medicated to 11.4 years in patients who received steroids (p < 0.0001). The majority of patients reported receiving care in line with guidelines, although we identified significant differences between countries and important shortcomings in prevention and treatment. Summarised, 35% of patients aged≥ nine years received no corticosteroid medication, 24% of all patients received no regular physiotherapy, echocardiograms were not performed regularly in 22% of patients, pulmonary function was not regularly assessed in 71% of non-ambulatory patients. Patients with regular follow-up by neuromuscular specialists were more likely to receive care according to guidelines, were better satisfied, and experienced shorter unplanned hospitalization periods.

[DISEASE BURDEN OP DUCHENNE MUSCULAR DYSTROPHY PATIENTS AND THEIR CAREGIVERS]. / DUCHENNE-FÉLE IZOMDISZTRÓFIÁVAL ÉLO BETEGEK ÉS GONDOZÓIK BETEGSÉGTERHEI.

BACKGROUND AND PURPOSE: Data on the disease burden of Duchenne Muscular Dystrophy are scarce in Hungary. The aim of this study was to assess patients' and their caregivers' health related quality of life and healthcare utilisations. METHODS: A cross sectional survey was performed as part of the European BURQOL-RD project. The EQ-5D-5L and Barthel Index questionnaires were applied, health care utilisations and patients' informal carers were surveyed. RESULTS: One symptomatic female carer, 50 children (boys 94%) and six adult patients (five males) participated in the study, the latter two subgroups were included in the analysis. The average age was 9.7 (SD = 4.6) and 24.3 (SD = 9.8) years, respectively. Median age at time of diagnosis was three years. The average EQ-5D score among children and adults was 0.198 (SD = 0.417) and 0.244 (SD = 0.322), respectively, the Barthel Index was 57.6 (SD = 29.9) and 53.0 (SD = 36.5). Score of satisfaction with healthcare (10-point Likert-scale) was mean 5.3 (SD = 2.1) and 5.3 (SD = 2.9). 15 children were hospitalised in the past 12 months for mean 12.9 (SD = 24.5) days. Two patients received help from professional carer. 25 children (mean age 11.1, SD = 4.4 years) were helped/supervisied by principal informal carer (parent) for mean 90.1 (SD = 44.4) hours/week and further family members helped in 21 cases. Correlation between EQ-5D and Barthel Index was strong and significant (0.731; p < 0.01) as well as with informal care time (-0.770; p < 0.01), but correlation with satisfaction with health care was not significant (EQ-5D: 0.241; Barthel Index: 0.219; informal care: -0.142). CONCLUSION: Duchenne muscular dystrophy leads to a significant deterioration in the quality of life of patients. Parents play outstanding role in the care of affected children. This study is the first in the Central and Eastern European region that provides quality of life data in this rare disease for further health economic studies.

Identification of a novel missense GLRA1 gene mutation in hyperekplexia: a case report.

INTRODUCTION: Hereditary hyperekplexia is a neurological disorder characterized by excessive startle responses with violent jerking to noise or touch, stiffening of the trunk and limbs, clenching of the fists and attacks of a high-frequency trembling. Hyperekplexia has a heterogeneous genetic background with several identified causative genes and demonstrates both dominant and recessive inheritance. Mutations in the glycine receptor alpha 1 subunit gene occur in about 30 percent of hyperekplexia cases. CASE PRESENTATION: In this study, we report the case of a Hungarian boy whose abnormal movements, muscle stiffness and convulsions were first noted when he was 4 days old. Neurological and electrophysiological investigation suggested the clinical diagnosis of hyperekplexia. CONCLUSIONS: Direct sequencing of the coding regions and the flanking introns of the glycine receptor alpha 1 subunit gene revealed a novel heterozygous missense mutation (c.211A/T, p.Ile71Phe). Genetic screening of our patient's family revealed that the clinically unaffected parents and sister do not carry the mutation, suggesting that the identified sequence change is a de novo mutation. Since hyperekplexia can have severe consequences, including sudden infant death due to laryngospasm and cardiorespiratory failure, identification of the causative genetic alteration(s) of the disease is high priority. Such knowledge is necessary for prenatal diagnosis, which would allow informed family planning and greater parental sensitivity to hyperekplexia 1-associated risks.

Mapping the differences in care for 5,000 spinal muscular atrophy patients, a survey of 24 national registries in North America, Australasia and Europe.

Spinal muscular atrophy (SMA) is an autosomal recessive genetic disorder characterised by the degeneration of motor neurons and progressive muscle weakness. It is caused by homozygous deletions in the survival motor neuron gene on chromosome 5. SMA shows a wide range of clinical severity, with SMA type I patients often dying before 2 years of age, whereas type III patients experience less severe clinical manifestations and can have a normal life span. Here, we describe the design, setup and utilisation of the TREAT-NMD national SMA patient registries characterised by a small, but fully standardised set of registry items and by genetic confirmation in all patients. We analyse a selection of clinical items from the SMA registries in order to provide a snapshot of the clinical data stratified by SMA subtype, and compare these results with published recommendations on standards of care. Our study included 5,068 SMA patients in 25 countries. A total of 615 patients were ventilated, either invasively (178) or non-invasively (437), 439 received tube feeding and 455 had had scoliosis surgery. Some of these interventions were not available to patients in all countries, but differences were also noted among high-income countries with comparable wealth and health care systems. This study provides the basis for further research, such as quality of life in ventilated SMA patients, and will inform clinical trial planning.

Behr's Syndrome is Typically Associated with Disturbed Mitochondrial Translation and Mutations in the C12orf65 Gene.

BACKGROUND: Behr's syndrome is a classical phenotypic description of childhood-onset optic atrophy combined with various neurological symptoms, including ophthalmoparesis, nystagmus, spastic paraparesis, ataxia, peripheral neuropathy and learning difficulties. OBJECTIVE: Here we describe 4 patients with the classical Behr's syndrome phenotype from 3 unrelated families who carry homozygous nonsense mutations in the C12orf65 gene encoding a protein involved in mitochondrial translation. METHODS: Whole exome sequencing was performed in genomic DNA and oxygen consumption was measured in patient cell lines. RESULTS: We detected 2 different homozygous C12orf65 nonsense mutations in 4 patients with a homogeneous clinical presentation matching the historical description of Behr's syndrome. The first symptom in all patients was childhood-onset optic atrophy, followed by spastic paraparesis, distal weakness, motor neuropathy and ophthalmoparesis. CONCLUSIONS: We think that C12orf65 mutations are more frequent than previously suggested and screening of this gene should be considered not only in patients with mitochondrial respiratory chain deficiencies, but also in inherited peripheral neuropathies, spastic paraplegias and ataxias, especially with pre-existing optic atrophy.

The TREAT-NMD Duchenne muscular dystrophy registries: conception, design, and utilization by industry and academia.

Duchenne muscular dystrophy (DMD) is an X-linked genetic disease, caused by the absence of the dystrophin protein. Although many novel therapies are under development for DMD, there is currently no cure and affected individuals are often confined to a wheelchair by their teens and die in their twenties/thirties. DMD is a rare disease (prevalence <5/10,000). Even the largest countries do not have enough affected patients to rigorously assess novel therapies, unravel genetic complexities, and determine patient outcomes. TREAT-NMD is a worldwide network for neuromuscular diseases that provides an infrastructure to support the delivery of promising new therapies for patients. The harmonized implementation of national and ultimately global patient registries has been central to the success of TREAT-NMD. For the DMD registries within TREAT-NMD, individual countries have chosen to collect patient information in the form of standardized patient registries to increase the overall patient population on which clinical outcomes and new technologies can be assessed. The registries comprise more than 13,500 patients from 31 different countries. Here, we describe how the TREAT-NMD national patient registries for DMD were established. We look at their continued growth and assess how successful they have been at fostering collaboration between academia, patient organizations, and industry.

Guidance in social and ethical issues related to clinical, diagnostic care and novel therapies for hereditary neuromuscular rare diseases: "translating" the translational.

Drug trials in children engage with many ethical issues, from drug-related safety concerns to communication with patients and parents, and recruitment and informed consent procedures. This paper addresses the field of neuromuscular disorders where the possibility of genetic, mutation-specific treatments, has added new complexity. Not only must trial design address issues of equity of access, but researchers must also think through the implications of adopting a personalised medicine approach, which requires a precise molecular diagnosis, in addition to other implications of developing orphan drugs. It is against this background of change and complexity that the Project Ethics Council (PEC) was established within the TREAT-NMD EU Network of Excellence. The PEC is a high level advisory group that draws upon the expertise of its interdisciplinary membership which includes clinicians, lawyers, scientists, parents, representatives of patient organisations, social scientists and ethicists. In this paper we describe the establishment and terms of reference of the PEC, give an indication of the range and depth of its work and provide some analysis of the kinds of complex questions encountered. The paper describes how the PEC has responded to substantive ethical issues raised within the TREAT-NMD consortium and how it has provided a wider resource for any concerned parent, patient, or clinician to ask a question of ethical concern. Issues raised range from science related ethical issues, issues related to hereditary neuromuscular diseases and the new therapeutic approaches and questions concerning patients rights in the context of patient registries and bio-banks. We conclude by recommending the PEC as a model for similar research contexts in rare diseases.

[Clinical manifestations, course and outcome of enzyme replacement therapy in Hungarian patients with Pompe's disease]. / Pompe-kór fenotípusvariációi, kórlefolyása és az enzimpótló kezelés eredményei: hazai tapasztalatok.

UNLABELLED: Pompe's disease is an autosomal recessive disease caused by deficiency of acid-alpha-glucosidase. AIMS AND METHODS: Authors analyzed the phenotype of 11 Hungarian patients with Pompe's disease and evaluated clinical parameters and response to enzyme replacement therapy during a long-term follow-up in 8 patients. RESULTS: One patient with atypical infantile form presented with cardiomyopathy and a very slow progression of motor deficits; after 2 years of enzyme replacement therapy no disability was present at the age 6 years. Another patient was asymptomatic at the age of 2.5 years. The adult onset form was characterized by slight to prominent limb-girdle myopathy with an age of onset between 20 and 50 years. In 3 of such cases respiratory insufficiency was also present. CONCLUSIONS: Hungarian patients with Pompe's disease presented with a wide phenotypic variability ranging from atypical early childhood form with slowly progressive course to late-onset limb-girdle myopathy with variable courses. Enzyme replacement therapy resulted in significant improvement in motor and respiratory functions in most of the patients.

[Role of associated alleles and hypomethylation status in the clinical expression of facioscapulohumeral muscular dystrophy]. / Facioscapulohumeralis izomdisztrófiával asszociált allélok és a hipometiláció szerepe a beteg fenotípus kialakulásában.

UNLABELLED: Autosomal dominant facioscapulohumeral muscular dystrophy (FSHD) is caused by contraction of the D4Z4 repeat region on 4q35. In addition, epigenetic modifying factors play a role in the complex pathomechanism of the disease. AIMS: Introduction of a new diagnostic panel in Hungary for the extended molecular analysis of the disease which also provides new insights into the pathomechanism. METHODS: In total, DNA samples of 185 clinically diagnosed FSHD patients and 71 asymptomatic relatives were analyzed by EcoRI and BlnI restriction digestion and Southern blot technique with probe p13-E11. Further investigations of the 4q35 alleles associated with the FSHD phenotype utilized qA and qB probes and a restriction analysis of the proximal D4Z4 unit by detecting a G/C SNP and the methylation status. RESULTS: From the patients analyzed 115 had the D4Z4 repeat contraction, whereas from 71 asymptomatic family members five harbored the pathogenic fragment size. In eight families, prenatal testing had to be offered with an outcome of four affected fetuses. Methylation test was performed in 31 genetically confirmed FSHD patients and hypomethylation status was detected in all cases. All the 115 confirmed patients had 4qA alleles with the G polymorphism. Translocation events between 4q35 and the homologous 10q26 regions were also detected. CONCLUSION: Molecular diagnosis of FSHD became a routine approach in Hungary thus supporting the work of the clinicians, improving quality of life and genetic counseling of the affected families. The provided results from this research suggest that FSHD is associated with complex epigenetic disease mechanisms.

Nemaline myopathy caused by mutations in the nebulin gene may present as a distal myopathy.

Mutations in the nebulin gene are the main cause of autosomal recessive nemaline myopathy, with clinical presentations ranging from mild to severe disease. We have previously reported a nonspecific distal myopathy caused by homozygous missense mutations in the nebulin gene in six Finnish patients from four different families. Here we describe three non-Finnish patients in two unrelated families with distal nemaline myopathy caused by four different compound heterozygous nebulin mutations, only one of which is a missense mutation. One of the mutations has previously been identified in one family with the severe form of nemaline myopathy. We conclude that nemaline myopathy and distal myopathy caused by nebulin mutations form a clinical and histological continuum. Nemaline myopathy should be considered as a differential diagnosis in patients presenting with an early-onset predominantly distal myopathy.

[Quantitative analysis of the genes determining spinal muscular atrophy]. / A spinalis izomatrophiát meghatározó survival motoneuron gének kvantitatív analízise.

Spinal muscular atrophy (SMA) is one of the most common autosomal recessive diseases, affecting approximately one in 10,000 live births and with a carrier frequency of approximately one in 35. The disease is caused by a deficiency of the ubiquitous protein survival of motor neuron (SMN), which is encoded by the SMN1 and SMN2 genes. Due to a single nucleotide polymorphism in exon 7, SMN2 produces less full-length transcript than SMN1 and cannot prevent neuronal cell death at physiologic gene dosages. On the other hand, the copy number of SMN2 affects the amount of SMN protein produced and the severity of the SMA phenotype. SMN gene dosage analysis can determine the copy number of SMN1 to detect carriers and patients heterozygous for the absence of SMN1 exon 7. This study provides copy number estimation of SMN1 gene by real-time PCR technique in 56 SMA type I., II., III. patients, 159 parents and healthy relatives and in 152 undefined SMA patients. Among the family members, 91 carriers have been detected and in 56 patients homozygous deletion of SMN1 exon 7 has been confirmed. Moreover, in 12 patients compound heterozygosity of SMN1 exon 7 mutation has been detected, thus providing the possible diagnosis of SMA. In 94 patients, copy number of SMN2 has also been evaluated and a good correlation has been found with the phenotype of the disease. Due to the genetic complexity and the high carrier frequency, accurate risk assessment and genetic counselling are particularly important for the families. These new results provide improvement of the diagnostic service in SMA in Hungary with focus on proper genetic counselling and possible enrolment of the patients in future therapeutic interventions.

Dystrophin gene analysis in Hungarian Duchenne/Becker muscular dystrophy families - detection of carrier status in symptomatic and asymptomatic female relatives.

A comprehensive study of the Hungarian Duchenne/Becker muscular dystrophy (DMD/BMD) families is presented. Deletions in the hot spots regions were identified by multiplex PCR, whereas rare mutations were detected by Southern blot and multiplex ligation-dependent probe amplification (MLPA) techniques. DMD/BMD disease was confirmed and exact deletion borders were determined in 19 out of 135 affected males using multiplex PCR. Additional exons involved as well as rare exon deletions were identified by MLPA in 71 male patients, whereas duplications were observed in seven patients. In two DMD patients, the entire dystrophin gene and adjacent genes were deleted. Out of the 95 female relatives, 41 proved to be carriers, including three manifesting carrier females. Using MLPA method, a large portion of the Hungarian DMD/BMD patients and their female relatives were exactly genotyped. For the first time, the incidence and prevalence of asymptomatic and symptomatic female carriers in Hungary was estimated.

[Clinical and genetic diagnosis of Dravet syndrome: report of 20 cases]. / A dravet-szindróma klinikai es genetikai diagnosztikájáról husz esetünk kapcsán.

OBJECTIVE AND BACKGROUND: Severe myoclonic epilepsy in infancy (SMEI; Dravet's syndrome) is a malignant epilepsy syndrome characterized by prolonged febrile hemiconvulsions or generalized seizures starting in the first year of life. Later on myoclonic, atypical absence, and complex partial seizures appear. When one of these seizure forms is lacking the syndrome of borderline SMEI (SMEB) is defined. Psychomotor delay resulting in mental retardation is observed during the second year of life. In most patients a de novo sodium channel alpha-1 subunit (SCN1A) mutation can be identified. By reviewing the clinical, laboratory, and neuroimaging data of our SMEI patients diagnosed between 2000 and 2008, we would like to share our experiences in this rare but challenging syndrome. Our results will facilitate the earlier and better diagnosis of Hungarian children with SMEI. PATIENTS AND METHODS: Clinical, EEG, MRI and DNA mutation data of 20 SMEI patients treated in the Bethesda Children's Hospital (Budapest) were reviewed. RESULTS: The first seizure appeared at age 6.3+/-3.0 months. At least one of the first two seizures were complex febrile seizures in 19/20 and unilateral seizures in 12/20 children. All children except for one showed hemiconvulsions at least once; all children had seizures lasting longer than 15 minutes. Eight of twenty patients had SMEB. DNA diagnostics identified an SCN1A mutation in 17 patients (6 missense, 4 nonsense, 4 frameshift, 2 splice site, 1 deletion) while 3 children had no mutation. CONCLUSION: Early diagnosis of SMEI is important for the avoiding unnecessary examinations and false therapies as well as for genetic counselling. Typical symptoms of SMEI are early and prolonged febrile hemiconvulsions with neurological symptoms, mental retardation and secondary seizure types later on. The presence of an SCN1A mutation supports the diagnosis. We propose the availability of molecular diagnostics and stiripentol therapy for SMEI children in Hungary

[Screening for hereditary neuromuscular disorders with molecular genetic methods in the Roma population of Hungary]. / Herediter neuromuscularis betegségek szûrése molekuláris genetikai módszerekkel hazai Roma populációban.

Recent medical genetic research has identified a number of novel, or previously known, but rare conditions, caused by private founder mutations. The Finnish and Ashkenazi Jew populations provide the best examples for identifying genes in unique genetic disorders. In these populations, research efforts and high-level medical services resulted in intense improvements of medical care and in organization of population-based screening programs. Hereditary disorders of the Roma populations are known for a long time. The genetic background of these diseases has been established by extensive molecular genetic studies. The Romas represent 6% of the Hungarian population and live under extremely bad health conditions. Therefore, our aim was to map the incidence of the hereditary neuromuscular disorders among the Hungarian Roma population. Moreover, we intended to provide proper information, genetic counseling and possible prevention strategies for the families at risk, which should represent a primer task in public health. Because of our experience in neuromuscular disorders, we choose six, frequent, autosomal recessive disorders for these clinical and genetic studies: hereditary motor and sensory neuropathy type Lom (HMSNL), hereditary motor and sensory neuropathy type Russe (HMSNR), congenital cataracts facial dysmorphism syndrome (CCFDN), limb-girdle muscular dystrophy 2C (LGMD2C), congenital myasthenic syndrome (CMS) and spinal muscular atrophy (SMA). Following identification of the founder mutations, the possibility of prenatal diagnosis and carrier screening for family members will contribute to the decrease of the recurrence risk for these severe, mostly untreatable disorders.