Congenital myasthenic syndrome in Israel: Genetic and clinical characterization.

The objective of the study was to evaluate the epidemiology of patients with congenital myasthenic syndrome (CMS) in Israel. Targeted mutation analysis was performed based on the clinical symptoms and electrophysiological findings for known CMS. Additional specific tests were performed in patients of Iranian and/or Iraqi Jewish origin. All medical records were reviewed and clinical data, genetic mutations and outcomes were recorded. Forty-five patients with genetic mutations in known CMS genes from 35 families were identified. Mutations in RAPSN were identified in 13 kinships in Israel. The most common mutation was c.-38A>G detected in 8 patients of Iranian and/or Iraqi Jewish origin. Four different recessive mutations in COLQ were identified in 11 kinships, 10 of which were of Muslim-Arab descent. Mutations in CHRNE were identified in 7 kinships. Less commonly detected mutations were in CHRND, CHAT, GFPT1 and DOK7. In conclusion, mutations in RAPSN and COLQ are the most common causes of CMS in our cohort. Specific mutations in COLQ, RAPSN, and CHRNE occur in specific ethnic populations and should be taken into account when the diagnosis of a CMS is suspected.

Congenital myopathies in Israeli families.

The clinical features of 37 patients from 32 Israeli families with congenital myopathies evaluated between 1983 and 2004 are described: 13 children were diagnosed with congenital fiber type disproportion, 10 had myotubular myopathy, 7 had nemaline myopathy, 5 had central core disease, 1 had actin myopathy, and 1 had multi-minicore disease. There were 7 families (22%) that had parental consanguinity, and 4 families (12%) had more than 1 patient with congenital myopathy. Of the patients, 31 (84%) presented with clinical symptoms before 4 months of age, and 6 children (16%) presented after 1 year of age. Thirteen children (35%) had a severe phenotype with chronic ventilatory dependence or mortality before the age of 11 years. Facial weakness was associated with a severe phenotype. There was a high rate of a severe clinical phenotype in patients with myotubular myopathy (60%) and in patients with nemaline myopathy (57%), whereas in patients with congenital fiber type disproportion and in patients with central core disease, the proportion of a severe phenotype was lower (23% and 0%, respectively).

Fukutin gene mutations in steroid-responsive limb girdle muscular dystrophy.

OBJECTIVE: Defects in glycosylation of alpha-dystroglycan are associated with several forms of muscular dystrophy, often characterized by congenital onset and severe structural brain involvement, collectively known as dystroglycanopathies. Six causative genes have been identified in these disorders including fukutin. Mutations in fukutin cause Fukuyama congenital muscular dystrophy. This is the second most common form of muscular dystrophy in Japan and is invariably associated with mental retardation and structural brain defects. The aim of this study was to determine the genetic defect in two white families with a dystroglycanopathy. METHODS: The six genes responsible for dystroglycanopathies were studied in three children with a severe reduction of alpha-dystroglycan in skeletal muscle. RESULTS: We identified pathogenic fukutin mutations in these two families. Affected children had normal intelligence and brain structure and shared a limb girdle muscular dystrophy (LGMD) phenotype, had marked elevation of serum creatine kinase, and were all ambulant with remarkable steroid responsiveness. INTERPRETATION: Our data suggest that fukutin mutations occur outside Japan and can be associated with much milder phenotypes than Fukuyama congenital muscular dystrophy. These findings significantly expand the spectrum of phenotypes associated with fukutin mutations to include this novel form of limb girdle muscular dystrophy that we propose to name LGMD2L.

Childhood macrophagic myofasciitis-consanguinity and clinicopathological features.

Macrophagic myofasciitis has been almost exclusively detected in adults only. We describe six children of Arab Moslem origin with this disorder. Three presented with hypotonia, developmental delay and seizures and were evaluated for a mitochondrial disorder. The other three children had hypotonia and predominantly motor delay. Five of the six families were consanguineous. A massive collection of macrophages was present in the fascia and adjacent epimysium in all biopsies. The macrophages were periodic-acid-Schiff positive and immunoreactive for CD68. One biopsy which was evaluated by electron microscopy and energy-dispersive X-ray microanalysis showed crystalline structures containing aluminum in macrophages. Two children with motor delay and hypotonia were treated with oral prednisone for 3 months with no clinical improvement. Genetic predisposition probably accounts for the variability in the prevalence of macrophagic myofasciitis in different populations. At least in childhood, there seems to be no connection between macrophagic myofasciitis as a pathological entity and the clinical symptoms and signs.

Parkinsonian features after streptococcal pharyngitis.

Bradykinesia and rigidity developed in a 10-year-old girl during an episode of Sydenham chorea. These parkinsonian features improved over 6 months. Serum analysis demonstrated elevated anti-streptolysin-O and anti-basal ganglia antibodies. We suggest that autoimmune antibodies may cause remitting parkinsonian signs subsequent to streptococcal tonsillitis as part of the spectrum of poststreptococcal CNS disease.

Prevalence of myotonic dystrophy in Israeli Jewish communities: inter-community variation and founder premutations.

In a comprehensive epidemiological survey among Jews living in Israel, the average prevalence of myotonic dystrophy (DM) was 15.7/10(5) (1 case in 6369) with intercommunity variations; the Ashkenazi Jews had the lowest rate, 5.7/10(5) (1 case in 17544) as compared to the rate in the Sephardim/Oriental Jews 20/10(5) (1 case in 5000) and the in the Yemenite Jews 47.3/10(5) (1 case in 2114). The rate of unrelated DM-sibships per 10(6) people of each community was used as an estimate of the transition rate from stable to unstable DMPK-(CTG)(n) alleles assuming that each transition is a beginning of a new DM sibship. This study indicated that the difference in the incidence of DM is a result of higher mutation rate in the non-Ashkenazi Jews (>50/10(6)) as compared to the rate in the Ashkenazi Jews (16.3/10(6)). The intragenic haplotype of the DM alleles was the same as that of the DM in many populations all over the world. However, two DM closely linked markers D19S207 and D19S112 were in linkage disequilibrium with the DM mutation in patients of Yemenite and Moroccan (the largest subgroup in the Sephardim Jews) extractions and not in the Ashkenazi patients. This observation indicated a common ancestral origin for the DM premutation in patients of the same ethnic origin. We concluded that the difference in the prevalence of DM among the Jewish communities is a consequence of founder premutations in the non-Ashkenazi Jewish communities.

Overuse of EEG in the evaluation of common neurologic conditions.

The objective of the present study was to analyze the diagnostic indications that most often prompt the referral of children and adolescents in the outpatient clinical pediatric practice for electroencephalographic evaluation and to check its utility in these clinical conditions. The electroencephalographic records of 547 consecutive children and adolescents (5-16 years of age) referred to a single community laboratory for the evaluation of various neurologic disorders were prospectively read by a single blinded investigator. Common diagnostic indications included the following: clinical seizures (42%), attention-deficit-hyperactivity disorder (23%), headaches (10.4%), syncope (9.9%), and tic disorder (4.9%). Overall, 76% of records were normal. Slowing of electroencephalographic activity was noted in 1% (attention-deficit-hyperactivity disorder) to 26% (probable epilepsy), and epileptiform activity in 53% of the probable and 29% of the clinically possible epileptics. Epileptiform activity was rarely found in the nonepileptic patients. The results of the present study demonstrate that standard interictal electroencephalogram is being overused during evaluation of various neurologic disorders in children and adolescents, suggesting that its use should be reserved for supporting the diagnosis in those cases in which epilepsy is a reasonable clinical possibility.