Identification of twelve novel mutations in patients with classic and variant forms of maple syrup urine disease

• Published in: Human mutation Vol. 22; no. 5; p. 417
• Main Authors: Henneke, Marco, Flaschker, Nadine, Helbling, Christoph, Müller, Martina, Schadewaldt, Peter, Gärtner, Jutta, Wendel, Udo
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.11.2003; Hindawi Limited
• Subjects: 3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide) - genetics; Acyltransferases - genetics; BCKD; BCKDHA; BCKDHB; DBT; DNA Mutational Analysis; Humans; Maple Syrup Urine Disease - diagnosis; Maple Syrup Urine Disease - genetics; MSUD; Mutation; mutation analysis
• ISSN: 1059-7794; 1098-1004
• DOI: 10.1002/humu.9187

Maple syrup urine disease (MSUD) is an autosomal recessive metabolic disorder of panethnic distribution caused by a deficiency of the activity of branched‐chain α‐ketoacid dehydrogenase (BCKD) complex. Mutations in the human BCKD genes E1α (BCKDHA), E1β (BCKDHB) and E2 (DBT) are known to result in MSUD, referred to as type Ia, Ib and II mutations respectively. In this study 16 patients with the classic severe form of MSUD and three patients with milder variant forms of the disease were investigated for mutations in the E1α‐, E1β‐ and E2‐gene by single‐strand conformation polymorphism (SSCP) analysis and DNA sequencing. The patients' clinical and biochemical phenotypes were well characterized. One novel type Ia missense mutation, eight novel type Ib (three missense, two nonsense, two small deletions, one small duplication) and three novel type II (two missense, one splice site) mutations were identified in patients. Moreover, eleven previously described mutations were detected: five type Ia (four missense, one nonsense), three type Ib mutations (two missense, one nonsense) and three type II mutations (two missense, one small deletion). Fourteen patients are homozygous for one single mutation, five patients are compound‐heterozygous for two different mutations affecting one of the three genes. Thus, in all 19 patients the identified mutations can most probably be considered the molecular basis of the disease. © 2003 Wiley‐Liss, Inc.