Treatment outcome in juvenile-onset myasthenia gravis.

INTRODUCTION: Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction. Approximately 10%-15% of MG patients have juvenile (<18 years of age) onset. We aimed to assess the clinical course, outcome, and subjectively perceived health status of a cohort of juvenile MG patients. METHODS: This was a retrospective analysis of medical records of 101 patients followed by a cross-sectional questionnaire study. RESULTS: The mean age of patients was 12.8 years at onset and 13.7 years at diagnosis. Ninety percent of the patients were seropositive. Over 40% of the patients were treated with immunosuppression and over 80% underwent thymectomy. The mean Myathenia Gravis Activities of Daily Living (MG-ADL) scale score was 2.48. At last follow-up, 30.9% of patients were in complete, stable remission; 77.8% perceived their health as good. DISCUSSION: The treatment outcome for juvenile MG is favorable, with a marked reduction of symptoms and good day-to-day activity achieved for most patients. Muscle Nerve 59:549-549, 2019.

Clinical, electrophysiological, and molecular findings in early onset hereditary neuropathy with liability to pressure palsy.

INTRODUCTION: The first episode of hereditary neuropathy with liability to pressure palsy (HNPP) in childhood is rare. METHODS: We analyzed retrospectively the data of 7 patients with a deletion in PMP22 and onset of symptoms before age 18 years. Direct sequencing of the LITAF (lipopolysaccharide-induced tumor necrosis factor) gene was performed in patients and family members. RESULTS: Clinical presentations varied from mononeuropathies to brachial plexopathy, with recurrent episodes in 4 patients. Electrophysiological abnormalities characteristic for HNNP were found in most subjects. Analysis of the LITAF gene revealed an Ile92Val polymorphism in 6 of 7 (86%) probands and 5 of 7 (83%) family members, over 4 times greater frequency than in the general population. CONCLUSIONS: Clinical suspicion of HNPP even when nerve conduction study results do not fulfill HNPP criteria should indicate genetic testing. In our patients, early-onset HNPP was associated frequently with isoleucine92valine LITAF polymorphism.

Multi-minicore myopathy: a clinical and histopathological study of 17 cases.

Multi-minicore disease (MmD) is a congenital myopathy morphologically defined by the multifocal lack of oxidative activity on light microscopy (LM) and multiple small zones of sarcomeric disorganization on electron microscopy (EM) as the main findings in muscle biopsy. We report on clinical and pathomorphological features of 17 patients diagnosed with multi-minicore myopathy at our department. Clinically, axial and proximal muscle weakness was the predominant distinguishing feature. Dysmorphic features such as high-arched palate and chest deformities were frequent findings. Limitation in cervical spine mobility was found in 4 cases. Most of our cases were slowly progressive but three fatal cases also occurred. Multifocal lack of oxidative activity was found in 16/22 biopsies on LM. Examination on EM enabled the final diagnosis of MmD in all cases. It is of special interest that in 3 patients fulfilling the criteria of pure congenital fibre type disproportion and in 2 cases of centronuclear myopathy, the findings of ultrastructural examination led us to a revised diagnosis of MmD. We postulate that all muscle biopsies with abnormal fibre proportion or centrally located nuclei as the only pathology on LM need to undergo careful EM evaluation to identify possible underlying multi-minicore disease.

Is a novel I214M substitution in the NEFL gene a cause of Charcot-Marie-Tooth disease? Functional analysis using cell culture models.

Recent studies have shown that mutations in neurofilament light subunit gene (NEFL) cause Charcot-Marie-Tooth (CMT) disease. Since the first description of the Gln333Pro mutation in the NEFL gene, 10 pathogenic mutations in the NEFL gene have been reported in patients affected with CMT disease. We report a novel I214M amino acid substitution in the NEFL gene in two unrelated patients affected with CMT. Because the I214M amino acid substitution in the NEFL protein was not detected in a CMT affected brother of the proband, its pathogenic effect became unclear. In order to determine whether this amino acid substitution is a benign polymorphism or causative of the disease, we performed a functional analysis of the mutant I214M neurofilament protein (NFL). Transfections of the mutant protein in cultured cells revealed an increased tendency to form highly compacted filamentous structures but no other alterations of neurofilament assembly or transport were observed. Furthermore, the sibling of one of the patients was also affected with CMT but did not have the I214M substitution. These data suggest that this I214M substitution in the NEFL gene was not a direct cause of the disease but could be a polymorphism or possibly a modifier of the CMT phenotype.

[Genetic investigations in facioscapulohumeral muscular dystrophy: a preliminary report]. / Badania genetyczne w dystrofii twarzowo-lopatkowo-ramieniowej--doniesienie wstepne.

Facioscapulohumeral muscular dystrophy (FSHD) is a primary muscle disorder with autosomal dominant inheritance. FSHD was mapped to chromosome 4 locus q35, but the gene is not yet known. It is characterised by progressive, often asymmetric, selective muscular weakness and great clinical variability. The aim of the study was to analyze 62 FSHD cases from 44 Polish families in which the diagnosis was confirmed by DNA analyses. FSHD diagnosis was based on the clinical findings and standardized investigations confirming primary muscular involvement (EMG, muscle biopsy). DNA analysis was based on EcoRI/BlnI restriction enzyme digestion followed by hybridization with P13E-11 molecular probe. In our material, we have found a relatively large percentage (41%) of big deletions (EcoRI/BlnI fragment of 10-15 kb [kilo bases]), which in the majority of cases (67%) was present in isolated cases. In 10 families (23%) the phenotype was assessed as severe. These are cases with the onset before the age of 10 and fast progression. "Middle sized" deletions (EcoRI/BlnI fragment of 16-29 kb) were prevalent in familial cases and present in 57% of families. "Small" deletion was found in one family (EcoRI/BlnI fragment of 30 kb). Somatic mosaicism was confirmed in one case. De novo mutations were shown in 11% of the examined families. The results of this study indicate that the bigger the deletion, the more severe the FSHD course, however there are some exceptions. A similar relationship has been shown by previous research. Molecular analyses are particularly important in atypical and sporadic cases. It is the first genetic presentation of a group of patients' with this kind of dystrophy in the Polish population.

[Identification of T274I mutation in the SMN1 gene in a patient with spinal muscular atrophy]. / Identyfikacja mutacji T2741 w genie SMN1 u chorego z rdzeniowym zanikiem miesni.

Proximal spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder characterised by degeneration of motor neurones in the spinal cord. The symptoms of the disease are determinated by mutations of SMN1 gene. About 98% of SMA patients show homozygous absence of exon 7 SMN1 gene, the rest carry small intragenic mutations. Molecular analysis of the presence of exon 7 SMN1 gene deletion is considered as the screening test for SMA. We present a case report of a 9 years old girl with progressive muscular weakness of limbs and trunk. Clinical examination followed by electromyography and muscle biopsy was interpreted as a diagnostic of SMA 3. Molecular analysis did not reveal deletion of exon 7 SMN1 gene. Extended molecular diagnostics using direct sequencing showed missence mutation T2741. Thus, the absence of homozygous deletion of exon 7 SMN1 gene does not exclude SMA diagnosis. All patients fulfilling the diagnostic criteria for SMA, as defined by the International SMA Consortium, without deletion of exon SMN1 gene, should be analysed using direct sequencing.

[Charcot-Marie Tooth type X (CMTX) disease: clinical and genetic characteristics of eleven patients]. / Choroba Charcot-Marie-Tooth typu X--charakterystyka kliniczno-genetyczna jedenastu chorych.

Charcot-Marie-Tooth type X disease (CMTX) is the second most frequent inherited neuropathy, after CMT1A type associated with 17p11.2-p12 duplication. CMTX is inherited as X dominant trait and is caused by point mutations in Cx32 gene. In the study the first Polish group of 11 patients with CMTX from 4 families is presented. The following four mutations were found in Cx32 gene: Gly110Asp, Val 152 Asp, Arg 183 His and Glu 208 Gly. CMTX is characterized by X dominant trait of inheritance, a mild clinical course in affected females and slowly progressive atrophy and weakness of distal limb muscles. Both electrophysiological and sural nerve biopsy studies show axonal changes with secondary demyelination.