title: Combined methylmalonic aciduria and homocystinuria cblC type of a Taiwanese infant with c.609G>A and C.567dupT mutations in the MMACHC gene.
abstract: Combined methylmalonic aciduria and homocystinuria, cobalamin (cbl)C type (cblC disease), the most common inborn error of vitamin B(12), is a rare disorder of intracellular cbl metabolism because of mutations in the MMACHC gene located in chromosome region 1p34.1. It has become possible to establish phenotype-genotype correlations and to observe ethnicity-related trends. This article provides detailed clinical manifestations and outcomes of a Taiwanese infant boy with early-onset cblC disease, heterozygous for c.609G>A and c.567dupT mutations, although there is limited information about cases with c.609G>A or c.567dupT mutation in the literature. He had no significant clinical abnormality during his neonatal period, whereas elevated C3 level was noted at newborn screening. He presented later with life-threatening manifestations and failure to thrive, which resolved through our treatment, although delayed development was still noted at 6 months of age. To date, all reported cblC patients with the c.609G>A mutation have been East Asians. Therefore, we suggest that c.609G>A should be included in the initial mutation screening tests for a cblC patient in East Asian populations.
authors.affiliation: Department of Pediatrics, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
authors.forename: Jenn-Tzong
authors.initials: JT
authors.lastname: Chang
authors.forename: Ying-Yao
authors.initials: YY
authors.lastname: Chen
authors.forename: Tze-Tze
authors.initials: TT
authors.lastname: Liu
authors.forename: Mei-Ying
authors.initials: MY
authors.lastname: Liu
authors.forename: Pao-Chin
authors.initials: PC
authors.lastname: Chiu
mesh_terms: D002352:Carrier Proteins / Q000235:genetics*; D005838:Genotype; D006712:Homocystinuria / Q000235:genetics*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008661:Metabolism, Inborn Errors / Q000235:genetics*; D008764:Methylmalonic Acid / Q000652:urine*; D009154:Mutation; D010088:Oxidoreductases; D014805:Vitamin B 12 / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D008764:Methylmalonic Acid; C508359:MMACHC protein, human; D010088:Oxidoreductases; D014805:Vitamin B 12