双胎新生儿枫糖尿病及其基因突变分析

目的 分析一对经典型枫糖尿病（MSUD）汉族双胎新生儿的临床特点及其相关基因的致病性突变，为MSUD早期诊治提供指导。方法 收集患儿的临床及影像学资料，提取患儿及其父母的外周血，检测枫糖尿病相关基因（BCKDHA，BCKDHB，DBT，DLD），确定基因突变位点，并进行生物信息学分析。结果 双胎患儿在BCKDHB基因上发现2个突变：错义突变c.304G > A（p.Gly102Arg）和无义突变c.331C > T（p.Arg111*），均为杂合子，且c.304G > A（p.Gly102Arg）为国际上未报道的新突变。其父亲携带错义突变c.304G > A（p.Gly102Arg），其母亲携带无义突变c.331C > T（p.Arg111*）。结论 BCKDHB基因c.331C > T（p.Arg111*）杂合突变是该双胎患儿的致病性突变，是枫糖尿病患儿临床表现的基因分子基础。

Maple syrup urine disease and gene mutations in twin neonates

Objective To investigate the clinical features of one pair of twin neonates with maple syrup urine disease (MSUD) in the Chinese Han population and pathogenic mutations in related genes, and to provide guidance for the early diagnosis and treatment of MSUD. Methods The clinical and imaging data of the twin neonates were collected. The peripheral blood samples were collected from the twin neonates and their parents to detect the genes related to MSUD (BCKDHA, BCKDHB, DBT, and DLD). The loci with gene mutations were identified, and a bioinformatic analysis was performed. Results Two mutations were detected in the BCKDHB gene, missense mutation c.304G>A (p.Gly102Arg) and nonsense mutation c.331C>T (p.Arg111*), and both of them were heterozygotes. The mutation c.304G>A (p.Gly102Arg) had not been reported in the world. Their father carried the missense mutation c.304G>A (p.Gly102Arg), and their mother carried the nonsense mutation c.331C>T (p.Arg111*). Conclusions The c.331C>T (p.Arg111*) heterozygous mutation in BCKDHB gene is the pathogenic mutation in these twin neonates and provides a genetic and molecular basis for the clinical features of children with MSUD.