A common mutation (epsilon1267delG) in congenital myasthenic patients of Gypsy ethnic origin.
ABSTRACT Mutation analysis of the acetylcholine receptor (AChR) epsilon subunit gene in patients with sporadic or autosomal recessive congenital myasthenic syndromes (CMS).
The nicotinic AChR of skeletal muscle is a neurotransmitter-gated ion channel that mediates synaptic transmission at the vertebrate neuromuscular junction. Mutations in its gene may cause congenital myasthenic syndromes. A recently described mutation in exon 12 of the AChR epsilon subunit (epsilon1267delG) disrupts the cytoplasmic loop and the fourth transmembrane region (M4) of the AChR epsilon subunit.
Forty-three CMS patients from 35 nonrelated families were clinically classified as sporadic cases of CMS (group III according to European Neuromuscular Centre consensus) and were analyzed for epsilon1267delG by PCR amplification and sequence analysis.
The authors report the complete genomic sequence and organization of the gene coding for the epsilon subunit of the human AChR (accession number AF105999). Homozygous epsilon1267delG was identified in 13 CMS patients from 11 independent families. All epsilon1267delG families were of Gypsy or southeastern European origin. Genotype analysis indicated that they derive from a common ancestor (founder) causing CMS in the southeastern European Gypsy population. Phenotype analysis revealed a uniform pattern of clinical features including bilateral ptosis and mild to moderate fatigable weakness of ocular, facial, bulbar, and limb muscles.
The mutation epsilon1267delG might be frequent in European congenital myasthenic syndrome patients of Gypsy ethnic origin. In general, patients (epsilon1267delG) were characterized by the onset of symptoms in early infancy, the presence of ophthalmoparesis, positive response to anticholinesterase treatment, and the benign natural course of the disease.
SourceAvailable from: Ajai Kumar Pathak
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ABSTRACT: Congenital myasthenic syndromes (CMS) are hereditary disorders of neuromuscular transmission characterized by fatigable muscle weakness. The number of cases recognized is increasing with improved diagnosis. To date we have identified over 300 different mutations present in over 350 unrelated kinships. The underlying genetic defects are diverse, involving a series of different genes with a variety of different phenotypes. The type of treatment and its effectiveness will depend on the underlying pathogenic mechanism. We aim to define the molecular mechanism for each mutation identified and feed this information back to the clinic as a basis to tailor patient treatment. Here, we describe some of the methods that can be used to define if a DNA sequence variant is pathogenic with reference to variants in DOK7. We highlight a new mechanism for disruption of AChR function, where a mutation in the AChR ɛ-subunit gene causes reduced ion channel conductance and discuss new methods for identifying gene mutations. The study of these disorders is proving highly informative for understanding the diverse molecular mechanisms that can underlie synaptic dysfunction.Annals of the New York Academy of Sciences 12/2012; 1275(1):63-9. DOI:10.1111/nyas.12000 · 4.31 Impact Factor
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ABSTRACT: The aim of this study was to analyze 22 cytokine polymorphisms in the Roma population from the Republic of Macedonia. The Roma population consists of 77 healthy unrelated individuals, residents of different geographical regions of the Republic of Macedonia (Skopje, Gostivar, and Kochani). Blood samples were collected after obtaining written consent. DNA was isolated from peripheral blood and 22 polymorphisms were typed: IL1A -889, IL1B -511, IL1B +3962, IL1R pst1 1970, IL1RN mspa11100, IL4RA +1902, IL12 -1188, IFNG utr5644, TGF-β1 cdn10, TGF-β1 cdn25, TNF-α -308, TNF-α -238, IL-2 -330, IL-2 +166, IL-4 -1098, IL-4 -590, IL-4 -33, IL-6 -174, IL-6 565, IL-10 -1082, IL-10 -819, and IL-10 -592. Cytokine genotyping was performed by PCR-SSP. The population genetics analysis package, PyPop, was used for analysis of the cytokine data. Fnd was negative and significantly different from 0 for IL-4 -590 (p of F=0.006), IL-10 -1082 (p of F=0.010), IFN utr5644 (p of F=0.024), IL-4 -1098 (p of F=0.026) and TGF-1 cdn25 (p of F=0.001) alleles, as well as for IL-2 haplotypes (p=0.025). Several SNPs (IL-12B -1188, IL-2 -330, IL-4 -1098, IL-4 -590, and IL-10 -1082) were not in HWP (p<0.05). A few SNPs (IL-12B -1188, IL-2 -330, IL-4 -1098, IL-4 -590, and IL-10 -1082) and several observed frequencies of cytokine diplotypes (IL-2/GG:TG, IL-2/TG:TG, IL-4/GCC:GCC, IL-4/TTC:TTC, IL-4/TTT:TTC, IL-10/GCC:GCC, IL-10/ATA:GCC, IL-10/ACC:GCC, and IL-10/ACC:ATA) were not in HWP and were significantly different from the expectations. Hardy Weinberg proportion could not be calculated for TNF genotypes and diplotypes because nearly all genotypes and diplotypes belong to GG genotype or GG:GG diplotype. The results of cytokine polymorphisms in Roma population can be used for characterization of the current genetic profile of the Gypsies, anthropological comparisons, as well as for the association studies with different diseases.Iranian journal of allergy, asthma, and immunology 12/2012; 11(4):282-293. · 1.01 Impact Factor