Retardation of myelination due to dietary vitamin B-12 deficiency: Cranial MRI findings

Vitamin B-12 deficiency is known to be associated with signs of demyelination, usually in the spinal cord. Lack of vitamin B-12, in the maternal diet during pregnancy has been shown to cause severe retardation of myelination in the nervous system. We report the case of a 14 1/2-month-old child of strictly vegetarian parents who presented with severe psychomotor retardation. This severely hypotonic child had anemia due to insufficient maternal intake of vitamin B-12 with associated megaloblastic anemia. MRI of the brain revealed severe brain atrophy with signs of retarded myelination, the frontal and temporal lobes being most severely affected. It was concluded that this myelination retardation was due to insufficient intake of vitamin B-12 and vitamin B-12 therapy was instituted. The patient responded well with improvement of clinical and imaging abnormalities, We stress the importance of MRI in the diagnosis and follow-up of patients with suspected diseases of myelination.