Growth Retardation, General Hypotonia, and Loss of Acquired Neuromotor Skills in the Infants of Mothers With Cobalamin Deficiency and the Possible Role of Succinyl-CoA and Glycine in the Pathogenesis

Vitamin B-12 (cobalamin, Chi) deficiency can cause metabolic, hematological, and neurological abnormalities. Adequate levels of succinyl-coenzyme A (CoA) cannot be synthesized from methylmalonyl-CoA because of the decreased activity of the methylmalonyl-CoA mutase enzyme that uses Cbl as the cofactor. Succinyl-CoA synthesis deficiency leads to decreased heme synthesis and gluconeogenesis. The reason of growth retardation can be gluconeogenesis deficiency together with heme synthesis deficiency whereas the reason of the neurological abnormalities can be glycine increase in the tissue due to decreased heme synthesis. We present 7 infants diagnosed with severe nutritional Cbi deficiency and discuss the role of succinyi-CoA and glycine in the possible pathogenesis in this article. Patients brought to our clinic with a complaint of growth retardation and diagnosed with nutritional CH deficiency were included in the study. There were 5 females and 2 males. The mean age was 11 +/- 2.30 (range 6-13) months. All patients had general muscular hypotonia and 4 had growth retardation. Neuromotor growth retardation was found in 4 of the children who had previously shown normal neuromotor development for age. The mean Chi level was 83.8 +/- 27.6 (45.6-114) pg/mL. The mean Chi level of the mothers was 155 +/- 56.6 (88-258) pg/mL. Six of the patients had anemia and 1 had thrombocytopenia. Mean corpuscular volume value was 91.5 +/- 12.211.. Following treatment, the muscle ton us of the patients improved, the anemia and growth retardation decreased, and the lost neuromotor abilities were recovered. Severe nutritional Cbl deficiency is an important nutritional disease where complications can be prevented with early treatment. When evaluating the pathogenesis, it should be noted that nutritional CH deficiency is a su.ccinyl-CoA synthesis deficiency.