A case report of a Myasthenic syndrome caused by a mutation in the CHRNE gene in Iranian population

Background and Objective: Congenital myasthenic syndrome (CMS) is the heterogeneous group of inherited disorders, characterized by dysfunction of neuromuscular junction (NMJ) transmission. The patients suffered from CMS showed the resembling clinical manifestations. CMS is genetically inherited and caused by vary of DNA mutation. Present case report aimed to examine the nucleotide variations in a panel of genes in CMS Iranian patient. Patient Report: The present case is a five years old boy with at least six CMS affected relatives in his family pedigree. His parents were second cousins. According to the neurology report, the patient has indicated Ptosis since birth with diurnal variation and high arch palate. The Muscle biopsy stained by H&E procedure reveals striated muscle tissue with a wide variation of fibre size. Atrophic fibres are round and/or angular and dispersed. ATPase reaction pH 9.4, 4.6 and 4.35 reveal prominent atrophy of type 2 fibres. Moreover, determination of blood cells showed that the higher amount of white blood cells (16.5 unit) in comparison to the normal range. After collecting the blood sample, DNA extracted by the manual method. Conclusion: Our investigations detected the homozygous single base pair deletion in exon 12 of the CHRNE gene (chr17:4802186delC). This region is conserved across mammalian evolution which wasn t filed in the 1000 genomes database. CHRNE variation possibly is classified as a significant variant on etiology of CMS and can be suggested that Iranian CMS population carry regional pathogenic mutations. Notably, it could be revealed via targeted as well as whole genome sequencing.

Keywords:

Congenital myasthenic , CMS , CHRNE