Cobalamin deficiency and related disorders in infancy and childhood

Evaluation of vitamin B12status in Egypt IV: Food consumption patterns among lactating mothers and their impact on the intake of the vitamin

The adequacy of vitamin B12 intake was assessed among 62 lactating mothers in the 2-32 weeks of lactation by an interactive 24-h recall and an open-ended food frequency questionnaire. Double portions of the foods consumed were sampled and assayed microbiologically for its vitamin B12 content. Based on the food item and its respective vitamin B12 content, combined with the usual portion size in grams and the frequency of consumption, a rapid calculator of approximate dietary vitamin B12 intake was developed. The estimated vitamin B12 intake averaged 4.17+/-0.74 microg/d. Only 25.8% of the lactating mothers had adequate vitamin B12 intake (>2.5 microg vitamin B12 daily). Three quarter of the studied population were consuming vitamin B12<2.5 microg/d. Out of those, 50% had estimated daily intake <2.0 microg/d. This percentage prevalence confirms the additional burden on the lactating mothers to satisfy the daily vitamin B12 requirement for its breast-fed baby.

Methylmalonic aciduria with homocystinuria: biochemical studies, treatment, and clinical course of a Cbl-C patient

A patient with infantile onset methylmalonic aciduria and homocystinuria (Cbl-C mutant) is described. Therapy with hydroxycobalamin, folate and vitamin B6 improved his condition. As hypomethioninaemia and homocystinaemia persisted, he was treated with intramuscular methylcobalamin, but without success. Treatment with betaine started at 25 months of age, normalized plasma methionine and elicited disappearance of homocystinaemia. Results of biochemical studies in cultured fibroblasts paralleled those described for other Cbl-C patients except that methylmalonyl-coenzyme A mutase activity in disrupted fibroblasts was in the normal range.

Vitamin B12 deficiency due to a strictly vegetarian diet in adolescence

A 14-year-old white girl suffered from severe neurologic disturbances caused by vitamin B12 deficiency, due to failure to provide vitamin B12 supplementation to a strictly vegetarian diet. The disturbances resolved completely following treatment with vitamin B12. Physicians should be alert to the necessity for vitamin B12 supplementation for strict vegetarians, who eat no meat, fish, eggs, or dairy products.

Clinical heterogeneity in cobalamin C variant of combined homocystinuria and methylmalonic aciduria

We describe two patients with methylmalonic aciduria and homocystinuria (Cbl C). The disorder was not diagnosed in patient 1 until 4 1/2 years of age; he had a history of fatigue, anorexia, delirium, and spasticity. Moderate megaloblastic bone marrow changes were observed, and there was hyperreflexia of the lower limbs. His condition improved clinically with hydroxycobalamin therapy. Patient 2 was hospitalized at 6 weeks of age because of lethargy and poor feeding. She was found to have macrocytosis. Despite an initial good clinical response to hydroxycobalamin, she developed a striking pigmentary retinopathy. Methylmalonic aciduria persisted in both patients, and homocystinuria persisted in patient 1 despite therapy. The diagnosis of Cbl C disease has been confirmed in both patients by biochemical studies of cultured fibroblasts, including complementation studies. The differences in age of onset and clinical findings together with the similar biochemical findings in these two patients demonstrate the heterogeneity of phenotypic expression in patients with apparently identical abnormalities of vitamin B12 metabolism.

Disorders of cobalamin metabolism

Recent developments in our knowledge of the biochemistry and metabolism of cobalamin have given us some insight into clinical disorders. N2O, which easily induces cobalamin deficiency, both in vivo and in vitro, has greatly contributed to the investigation of the cobalamin deficient state, especially in relation to folate and amino acid metabolism. Demonstration of the cobalamin analog in human serum and a new enzyme which requires cobalamin as a coenzyme has led to recent increased interest in this field. The disorders of cobalamin metabolism will be summarized briefly as well as those areas currently of particular interest.

Vitamin B12 neuropathy in a 6 year old

Gross neuropathy consequent upon selective malabsorption of vitamin B12 was diagnosed in a 6 year old Bangladeshi girl brought to Great Britain for further investigation of an unexplained illness of three years' duration. The initial peripheral blood count was normal. Treatment with vitamin B12 has led to substantial recovery.