Clinical phenotype and genotype analysis on a family of Becker muscular dystrophy caused by a novel missense mutation of DMD gene

Abstract

Objective To summarize the phenotype and genotype of a family of Becker muscular dystrophy (BMD) caused by a novel missense mutation of DMD gene. Methods and Results Clinical data of one BMD proband and the family members were collected. Next-generation sequencing technology was used to detect possible gene mutation in the proband, a 25-year-old male BMD patient. Sanger sequencing technology was used to further detect possible mutation of c.4449T > G (p.Asn1483Lys) locus of DMD gene in the proband's mother and younger sister. The analysis was carried out combined with clinical data of the proband and other family members. Results showed the patient had the same phenotype as his two uncles (mother's brothers), who presented pseudohypertrophy of calf muscles, atrophy and weakness of proximal lower extremities and elevated serum creatine kinase (CK). Gene mutation analysis demonstrated a novel missense mutation c.4449T > G (p.Asn1483Lys) in exon 34 of DMD gene in the proband. The proband's mother and younger sister were carriers of mutated gene. Combined with the clinical manifestations of proband's uncles, the patient was clearly diagnosed as BMD, and the family was clearly diagnosed as BMD pedigree. Besides, there was a common separation phenomenon in the family. Conclusions The study described a novel missense mutation in exon 34 c.4449T > G (p.Asn1483Lys) of DMD gene which caused BMD. This enriches the mutation map of DMD gene, and also provides valuable information for genetic counseling and prenatal diagnosis.

DOI: 10.3969/j.issn.1672-6731.2019.05.008