Phenotype/genotype analysis of 4 cases of LMNA related congenital muscular dystrophy with inflammatory changes

Abstract

Objective To analyze the clinical characteristics, muscle pathological features and pathogenic gene mutation in 4 cases with LMNA-related congenital muscular dystrophy(L-CMD). Methods Clinical data of the probands and the parents were collected. Skeletal muscle specimens were biopsied from the probands for pathological analysis. Genomic DNA and RNA were extracted from peripheral blood leukocytes, and PCR, reverse transcription(RT)-PCR and DNA direct sequencing were employed to analyze the LMNA gene to determine the gene mutation and confirm the pathogenicity. Results Four patients had symptoms from fetal period to several months after birth. They presented with motor retardation, muscle weakness with prominent the proximal upper limbs, distal lower limbs and neck extensor, hypotonia, contractures, with mild to moderate elevation of CK level. The muscle biopsies showed muscular dystrophic and with inflammatory changes, and the abnormal nuclear morphology was observed with transmission electron microscopy. Genetic analysis of them detected 4 dominant de novo mutations. Three of them had unreported pathogenic mutations. The same sites of the LMNA gene were wild type in their parents. Conclusions Four cases of L-CMD are genetically identified. Genetic counseling of the family can be possible. The patients should be considered LMNA gene mutation of they present themselves with muscle weakness with the proximal upper limbs, distal lower limbs and neck extensor, hypotonia, contractures, mild to moderate elevation of CK level, and if the biopsies show muscular dystrophic changes but also with inflammatory changes should be considered LMNA gene mutation. Genetic analysis is the most reliable method for diagnosing L-CMD. Key words: LMNA related congenital muscular dystrophy; Inflammatory myopathy; LMNA gene; Mutation