Metabolic Complications and Neurological Symptoms of Vitamin B 12Deficiency in Infants of Vegetarian Mothers

Overview

Background.
Serious hematological, metabolic and neurological complications owing to the nutritional deficiencyof vitamin B 12 may occur in infants of mothers on a strict vegetarian diet.Methods and Results. The mother of the first child was a strict vegetarian. She had an elevated urinarymethylmalonic acid level and a low concentration of serum vitamin B 12 . Her 13-month-old daughter was exclusivelybreast-fed until the age of 9 month and then she was fed only vegetables. Physical examination revealed psychomotoricretardation, apathy, muscular hypotonia, abnormal movements and failure to thrive. Laboratory analysis showeda megaloblastic anaemia, a low level of vitamin B 12 and methylmalonic aciduria. MRI of the brain revealed diffusefrontotemporoparietal atrophy and retardation of meylination. After treatment with vitamin B 12 supplements,abnormal movements disappeared and development improved, but a mild generalised hypotonia continued. A cranialMRI 9 months after treatment still showed signs of retardation of myelination. The second patient, an 8 month-oldmale, son of a strict vegetarian mother too, was referred for investigation of psychomotoric retardation, hypotonia,dyskinesia, failure to thrive and microcephaly. He was breast-fed and from 6 month of age he had also received fruitjuices. Laboratory analysis revealed megaloblastic anaemia, high methylmalonic aciduria and homocystinuria. Thepatient’s and his mother’s serum level of vitamin B 12 were low. After treatment with vitamin B 12 supplements,biochemical and metabolic markers of disease were normal but there continued a generalised hypotonia, microcep-haly and language delay.Conclusion. Our observations emphasize the health complications of nutritional cobalamine deficiency anda requirement of clinical, biochemical and metabolic monitoring in infants within strict vegetarian families.

Key words:
vegetarian diet, vitamin B 12 , methylmalonic aciduria, homocystinuria, microcephaly, psychomotoricretardation.