Outcomes of patients with cobalamin C deficiency: A single center experience

• Published in: JIMD reports Vol. 57; no. 1; pp. 102 - 114
• Main Authors: Bourque, Danielle K., Mellin‐Sanchez, Lizbeth E., Bullivant, Garrett, Cruz, Vivian, Feigenbaum, Anette, Hewson, Stacy, Raiman, Julian, Schulze, Andreas, Siriwardena, Komudi, Mercimek‐Andrews, Saadet
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.01.2021
• Subjects: Acids; Age; Child development; Clinical outcomes; cobalamin C; Cohort analysis; Drug dosages; Ethnicity; Failure to thrive; global developmental delay; Homocysteine; homocystinuria; Ischemia; Learning disabilities; Medical imaging; Medical screening; methylmalonic acid; Microcephaly; Neuroimaging; newborn screening; Patients; Research ethics; Research Report; Research Reports; Stroke; Urine; methylmalonic acid; cobalamin C; homocystinuria; global developmental delay; newborn screening; stroke
• DOI: 10.1002/jmd2.12179
• ISSN: 2192-8312; 2192-8304

Biallelic variants in MMACHC results in the combined methylmalonic aciduria and homocystinuria, called cobalamin (cbl) C (cblC) deficiency. We report 26 patients with cblC deficiency with their phenotypes, genotypes, biochemical parameters, and treatment outcomes, who were diagnosed and treated at our center. We divided all cblC patients into two groups: group 1: SX group: identified after manifestations of symptoms (n = 11) and group 2: NB group: identified during the asymptomatic period via newborn screening (NBS) or positive family history of cblC deficiency (n = 15). All patients in the SX group had global developmental delay and/or cognitive dysfunction at the time of the diagnosis and at the last assessment. Seizure, stroke, retinopathy, anemia, cerebral atrophy, and thin corpus callosum in brain magnetic resonance imaging (MRI) were common in patients in the SX group. Global developmental delay and cognitive dysfunction was present in nine patients in the NB group at the last assessment. Retinopathy, anemia, and cerebral atrophy and thin corpus callosum in brain MRI were less frequent. We report favorable outcomes in patients identified in the neonatal period and treated pre‐symptomatically. Identification of cblC deficiency by NBS is crucial to improve neurodevelopmental outcomes.