OBJECTIVETo carry out mutation analysis for a pedigree affected with maple syrup urine disease (MSUD).

METHODSClinical data of the proband was collected. Potential mutations of the BCKDHA and BCKDHB genes were analyzed by PCR and Sanger sequencing. Prenatal diagnosis was provided to a high-risk fetus at 12th gestational week through chorionic villus sampling.

RESULTSTwo heterozygous mutations c.284G>C (p.Gly95Ala) and c.853C>T (p.Arg285*) of the BCKDHB gene were identified in the proband, which were inherited from his mother and father, respectively. Among these, c.853C>T (p.Arg285*) was known to be pathogenic, while c.284G>C (p.Gly95Ala) was a novel mutation. Prenatal diagnosis showed that the fetus has inherited the c.284G>C (p.Gly95Ala) mutation from its mother but no mutation from its father. After birth, the infant appeared to be healthy.

CONCLUSIONThe compound heterozygous mutations c.284G>C (p.Gly95Ala) and c.853C>T (p.Arg285*) probably underlie the pathogenesis of MUSD in the proband. Mutation analysis can facilitate prenatal diagnosis and genetic counseling for the affected families.