0000000000148833
AUTHOR
María José Chumillas
The gene encoding ganglioside-induced differentiation-associated protein 1 is mutated in axonal Charcot-Marie-Tooth type 4A disease
We identified three distinct mutations and six mutant alleles in GDAP1 in three families with axonal Charcot-Marie-Tooth (CMT) neuropathy and vocal cord paresis, which were previously linked to the CMT4A locus on chromosome 8q21.1. These results establish the molecular etiology of CMT4A (MIM 214400) and suggest that it may be associated with both axonal and demyelinating phenotypes.
Mutations in theMORC2gene cause axonal Charcot–Marie–Tooth disease
Charcot-Marie-Tooth disease (CMT) is a complex disorder with wide genetic heterogeneity. Here we present a new axonal Charcot-Marie-Tooth disease form, associated with the gene microrchidia family CW-type zinc finger 2 (MORC2). Whole-exome sequencing in a family with autosomal dominant segregation identified the novel MORC2 p.R190W change in four patients. Further mutational screening in our axonal Charcot-Marie-Tooth disease clinical series detected two additional sporadic cases, one patient who also carried the same MORC2 p.R190W mutation and another patient that harboured a MORC2 p.S25L mutation. Genetic and in silico studies strongly supported the pathogenicity of these sequence variant…
Phenotypical features of two patients diagnosed with PHARC syndrome and carriers of a new homozygous mutation in the ABHD12 gene.
Abstract PHARC (Polyneuropathy, Hearing loss, Ataxia, Retinitis pigmentosa and Cataracts) (MIM# 612674 ) is an autosomal recessive neurodegenerative disease caused by mutations in the ABHD12 gene. We evaluated two Spanish siblings affected with pes cavus, sensorimotor neuropathy, hearing loss, retinitis pigmentosa and juvenile cataracts in whom the genetic test of ABHD12 revealed a novel homozygous frameshift mutation, c.211_223del (p.Arg71Tyrfs*26). The earliest clinical manifestation in these patients was a demyelinating neuropathy manifested with a Charcot-Marie-Tooth phenotype over three decades. Progressive hearing loss, cataracts and retinitis pigmentosa appeared after the age of 30. …
Charcot-Marie-Tooth disease: Genetic and clinical spectrum in a Spanish clinical series
Objectives: To determine the genetic distribution and the phenotypic correlation of an extensive series of patients with Charcot-Marie-Tooth disease in a geographically well-defined Mediterranean area. Methods: A thorough genetic screening, including most of the known genes involved in this disease, was performed and analyzed in this longitudinal descriptive study. Clinical data were analyzed and compared among the genetic subgroups. Results: Molecular diagnosis was accomplished in 365 of 438 patients (83.3%), with a higher success rate in demyelinating forms of the disease. The CMT1A duplication (PMP22 gene) was the most frequent genetic diagnosis (50.4%), followed by mutations in the GJB1…
Phenotype and natural history of inherited neuropathies caused byHSJ1c.352+1G>A mutation
Mutations in the HSJ1 ( Heat-Shock Protein J1 ) gene, also called DNAJB2 (DnaJ (Hsp40) homologue, subfamily B, member 2), have been recently described as a cause of hereditary neuropathies. The HSJ1 c.352+1G>A mutation in homozygote state has been reported as the causative mutation in a single family with autosomal recessive distal hereditary motor neuropathy (dHMN).1 Since then, two other families with different HSJ1 mutations have been described: one with a dHMN phenotype and the other with a Charcot-Marie-Tooth disease type 2 (CMT2) phenotype.2 We identified the HSJ1 c.352+1G>A mutation in 10 patients who underwent long-lasting follow-up. We describe their phenotype and clinical evolutio…
Distribution and genotype-phenotype correlation of GDAP1 mutations in Spain
AbstractMutations in the GDAP1 gene can cause Charcot-Marie-Tooth disease. These mutations are quite rare in most Western countries but not so in certain regions of Spain or other Mediterranean countries. This cross-sectional retrospective multicenter study analyzed the clinical and genetic characteristics of patients with GDAP1 mutations across Spain. 99 patients were identified, which were distributed across most of Spain, but especially in the Northwest and Mediterranean regions. The most common genotypes were p.R120W (in 81% of patients with autosomal dominant inheritance) and p.Q163X (in 73% of autosomal recessive patients). Patients with recessively inherited mutations had a more seve…
Netrin-1 receptor antibodies in thymoma-associated neuromyotonia with myasthenia gravis.
Objective:To identify cell-surface antibodies in patients with neuromyotonia and to describe the main clinical implications.Methods:Sera of 3 patients with thymoma-associated neuromyotonia and myasthenia gravis were used to immunoprecipitate and characterize neuronal cell-surface antigens using reported techniques. The clinical significance of antibodies against precipitated proteins was assessed with sera of 98 patients (neuromyotonia 46, myasthenia gravis 52, thymoma 42; 33 of them with overlapping syndromes) and 219 controls (other neurologic diseases, cancer, and healthy volunteers).Results:Immunoprecipitation studies identified 3 targets, including the Netrin-1 receptors DCC (deleted i…
The EGR2 gene is involved in axonal Charcot-Marie-Tooth disease
Background and purpose A three-generation family affected by axonal Charcot−Marie−Tooth disease (CMT) was investigated with the aim of discovering genetic defects and to further characterize the phenotype. Methods The clinical, nerve conduction studies and muscle magnetic resonance images of the patients were reviewed. A whole exome sequencing was performed and the changes were investigated by genetic studies, in silico analysis and luciferase reporter assays. Results A novel c.1226G>A change (p.R409Q) in the EGR2 gene was identified. Patients presented with a typical, late-onset axonal CMT phenotype with variable severity that was confirmed in the ancillary tests. The in silico studies sho…