To describe the phenotypic spectrum of dysferlin (DYSF) gene mutations (which cause dysferlinopathies, autosomal recessive muscular dystrophies) in patients with a dysferlin protein deficiency. Design: Clinical, biological, and pathological data from 40 patients were reviewed. The diagnosis of dysferlinopathy was based on the absence or strong reduction of dysferlin in muscle, and confirmed by mutational screening of the DYSF gene. Setting: Two French neuromuscular diseases centers (in Paris and Marseilles). Results: Two main dysferlinopathy phenotypes are well recognized: Miyoshi myopathy and limb-girdle muscular dystrophy type 2B. Typical Miyoshi myopathy and limb-girdle muscular dystrophy type 2B were found in 20 (50%) patients only. Unusual phenotypes included a mixed phenotype, referred to as "proximodistal," combining distal and proximal onset in 14 (35%) patients, pseudometabolic myopathy in 4 (10%), and asymptomatic hyperCKemia (an increased serum creatine kinase level) in 2 (5%). The disease may worsen rapidly, and 10 (25%) patients were initially misdiagnosed as having polymyositis. We suggest a relationship between proximodistal phenotype, inflammation, and severity. Conclusion: In addition to typical Miyoshi myopathy and limb-girdle muscular dystrophy type 2B, dysferlinopathies are a clinically heterogeneous group of disorders ranging from asymptomatism to severe functional disability.
ERSpublicationsGene panel sequencing unravels the genetic architecture of pulmonary hypertension in adult and paediatric cases, emphasises the importance of BMPR2, EIF2AK4, BMP9 and TBX4 mutations, and suggests BMP10 as a new gene for the disease http://ow.ly/Oxes30mXnrI
DYSF encoding dysferlin is mutated in Miyoshi myopathy and Limb-Girdle Muscular Dystrophy type 2B, the two main phenotypes recognized in dysferlinopathies. Dysferlin deficiency in muscle is the most relevant feature for the diagnosis of dysferlinopathy and prompts the search for mutations in DYSF. DYSF, located on chromosome 2p13, contains 55 coding exons and spans 150 kb of genomic DNA. We performed a genomic analysis of the DYSF coding sequence in 34 unrelated patients from various ethnic origins. All patients showed an absence or drastic decrease of dysferlin expression in muscle. A primary screening of DYSF using SSCP or dHPLC of PCR products of each of 55 exons of the gene was followed by sequencing whenever a sequence variation was detected. All together, 54 sequence variations were identified in DYSF, 50 of which predicting either a truncated protein or one amino-acid substitution and most of them (34 out of 54) being novel. In 23 patients, we identified two pathogenic mutations, while only one was identified in 11 patients. These mutations were widely spread in the coding sequence of the gene without any mutational "hotspot."
This study provides Class III evidence that assays for hypomethylation within the D4Z4 region accurately distinguish patients with FSHD from individuals with D4Z4 contraction without FSHD.
E346causing mutations, confirming the diagnosis of primary Dysferlinopathy on a genetic basis. Furthermore, one mutation was identified in 30 patients, without identification of a second deleterious allele. We are currently developing complementary analysis for patients in whom only one or no disease-causing allele could be identified using the genomic screening procedure. Altogether, 64 novel mutations have been identified in this cohort, which corresponds to approximately 25% of all DYSF mutations reported to date. The mutational spectrum of this cohort significantly shows a higher proportion of nonsense mutations, but a lower proportion of deleterious missense changes as compared to previous series.
Background: Juvenile Huntington disease (JHD) is a rare clinical entity characterized by an age at onset younger than 20 years. Patients usually have an expansion of more than 60 CAG repeats in the Huntington disease (HD) gene, and the disease is usually inherited from the father. In general, precise age at onset is difficult to assess in HD because of insidious onset and anosognosia. Onset of motor difficulty signs is usually used to define age at onset. Objectives: To evaluate diagnosis delay in patients with JHD and to analyze the clinical and genetic features of JHD.
Dysferlinopathies encompass a large variety of neuromuscular diseases characterized by the absence of dysferlin in skeletal muscle and an autosomal recessive mode of inheritance. So far, three main phenotypes have been reported: Miyoshi myopathy (MM), limb girdle muscular dystrophy type 2B (LGMD 2B), and distal myopathy with anterior tibial onset (DMAT). A growing number of clinical variants have recently been described with a much wider range of symptoms and onset. Although rare, dysferlinopathies can account for up to 30% of progressive recessive muscular dystrophies in certain geographical areas, notably in the Middle East and the Indian subcontinent. Dysferlin is a large protein involved in membrane repair and vesicle trafficking and interacts probably with important immunological pathways. New insights in its pathophysiology may result in innovative therapies in the near future.
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