title: Genetic and cellular studies of oxidative stress in methylmalonic aciduria (MMA) cobalamin deficiency type C (cblC) with homocystinuria (MMACHC).
abstract: Methylmalonic aciduria (MMA) cobalamin deficiency type C (cblC) with homocystinuria (MMACHC) is the most frequent genetic disorder of vitamin B(12) metabolism. The aim of this work was to identify the mutational spectrum in a cohort of cblC-affected patients and the analysis of the cellular oxidative stress and apoptosis processes, in the presence or absence of vitamin B(12). The mutational spectrum includes nine previously described mutations: c.3G>A (p.M1L), c.217C>T (p.R73X), c.271dupA (p.R91KfsX14), c.331C>T (p.R111X), c.394C>T (p.R132X), c.457C>T (p.R153X), c.481C>T (p.R161X), c.565C>A (p.R189S), and c.615C>G (p.Y205X), and two novel changes, c.90G>A (p.W30X) and c.81+2T>G (IVS1+2T>G). The most frequent change was the known c.271dupA mutation, which accounts for 85% of the mutant alleles characterized in this cohort of patients. Owing to its high frequency, a real-time PCR and subsequent high-resolution melting (HRM) analysis for this mutation has been established for diagnostic purposes. All cell lines studied presented a significant increase of intracellular reactive oxygen species (ROS) content, and also a high rate of apoptosis, suggesting that elevated ROS levels might induce apoptosis in cblC patients. In addition, ROS levels decreased in hydroxocobalamin-incubated cells, indicating that cobalamin might either directly or indirectly act as a scavenger of ROS. ROS production might be considered as a phenotypic modifier in cblC patients, and cobalamin supplementation or additional antioxidant drugs might suppress apoptosis and prevent cellular damage in these patients.
authors.affiliation: Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular-Severo Ochoa (SO) Universidad Autónoma de Madrid (UAM)-Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Richard
authors.forename: Ana
authors.initials: A
authors.lastname: Jorge-Finnigan
authors.forename: Judit
authors.initials: J
authors.lastname: Garcia-Villoria
authors.forename: Begoña
authors.initials: B
authors.lastname: Merinero
authors.forename: Lourdes R
authors.initials: LR
authors.lastname: Desviat
authors.forename: Laura
authors.initials: L
authors.lastname: Gort
authors.forename: Paz
authors.initials: P
authors.lastname: Briones
authors.forename: Fátima
authors.initials: F
authors.lastname: Leal
authors.forename: Celia
authors.initials: C
authors.lastname: Pérez-Cerdá
authors.forename: Antonia
authors.initials: A
authors.lastname: Ribes
authors.forename: Magdalena
authors.initials: M
authors.lastname: Ugarte
authors.forename: Belén
authors.initials: B
authors.lastname: Pérez
mesh_terms: D017209:Apoptosis / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics*; D056726:Genetic Association Studies; D006712:Homocystinuria / Q000235:genetics*; D006801:Humans; D008928:Mitochondria / Q000378:metabolism; D018384:Oxidative Stress; D010088:Oxidoreductases; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D014805:Vitamin B 12 / Q000494:pharmacology; D014806:Vitamin B 12 Deficiency / Q000235:genetics*
chemical_list: D002352:Carrier Proteins; D017382:Reactive Oxygen Species; C508359:MMACHC protein, human; D010088:Oxidoreductases; D013482:Superoxide Dismutase; D014805:Vitamin B 12