Clinical, myopathological and genetic mutations features of limb girdle muscular dystrophy 2I / 中华神经科杂志

ABSTRACT

Objective To summary the pathological and genetic features in nine Chinese limb girdle muscular dystrophy 2I (LGMD2I) patients.Methods Nine LGMD2I patients were recruited from Peking University First Hospital between 2011 and 2016, who came from nine unrelated and non-consanguineous families.The mean age of onset was (8.2±5.2) years (2 to 19 years), and the mean disease duration was (10.4±6.1) years (1 to 24 years).There were six males and three females, present with weakness in limb girdle muscles, four of whom accompanied with calf hypertrophy and three with scapular winging.Serum creatine kinase was 964-23 131 U/L (normal 25-190 U/L).Five of them who conducted electromyogram showed myogenic pattern.Muscle biopsy and next generation sequencing were performed in these patients, then sanger sequencing was performed to determine whether the variants co-segregated with the phenotype in these families.Results Muscle biopsy revealed myopathy features in six patients, dystrophic change in one, and only mild changes in two.Major histocompatibility complex-Ⅰ was positive in six cases, and rimmed vacuoles were found in two.There were seven mutations in fukutin-related protein (FKRP) gene.A reported mutation of c.545A>G (p.Y182C) appeared in eight cases, including three homozygotes and five compound heterozygotes.The mutation of c.1067T>C (p.Ile356Thr) was reported too.And c.1263C>A (p.Tyr421X), c.534G>T(p.Thr178Cys), c.1027G>C (p.Glu343Gln), c.1027G>T(p.Glu343X), c.1448A>G (p.Tyr483Cys) were found to be novel mutations.Conclusions LGMD2I showed large variation in myopathology.The missense mutation A545G(Y182C) is a hot spot of FKRP gene in our series.