A Novel Mutation in the BCKDHB Gene Causes in an Iranian Child Classic Maple Syrup Urine Disease

Background: Maple syrup urine disease (MSUD) is a rare metabolic disorder caused by deficiency in branched chain alpha-keto acid dehydrogenase complex (BCKD). Methods: In this study, the coding regions and flanking splice sites of the BCKDHA, BCKDHB, DBT and DLD genes have been sequenced in an Iranian 3 years old girl. Results: A novel homozygous mutation (p.Glu330Lys) was detected in the BCKDHB gene. In silico analysis showed significant change in the 3-D protein Structure. Conclusions: This alteration probably affects the structure and function of the E1β subunit of BCKD complex.