A variety of abnormal movements in 13 cases with nutritional cobalamin deficiency in infants

Hypothesis: Abnormal movements such as tremor, myoclonus, and choreoathetosis due to infantile nutritional vitamin B12 (Cbl, cobalamin) deficiency or after Cbl injection have been recognized for many years. However, nutritional Cbl deficiency may be more common than recognized and a variety of the abnormal movements may be beyond our estimates. Materials and methods: This study analyzed a variety of abnormal movements such as involuntary eye movements, limb and body contractions, and gasping as well as clinical, metabolic, radiologic, and treatment results in 13 infants with nutritional Cbl deficiency. This is a retrospective study based on observation and experience. Results: This study included 13 infants (11 boys and 2 girls) with a large spectrum of abnormal movements, the mean age at admission was 8.3 months with a range of 3–22 months. All patients were breastfeeding. In seven cases and their mothers serum vitamin B12 levels were below 200 pg/ml. About one-third of cases serum vitamin B12 levels were over 200 pg/ml. Clinically, mild hypotonia was present in 5 cases, inadequate social interactions in 2 cases, and sensorineural hearing loss in one case. Brain MRI showed frontotemporal enlarged subarachnoid spaces and thinning of the corpus callosum in two cases. EEG examinations were normal in all cases at admission. All cases recovered rapidly within one month with treatment. Conclusion: Nutritional Cbl deficiency is a treatable disease that should be considered in the etiology of a variety of movement abnormalities in infants even if serum vitamin B12 values and neurological development are nor- mal.
Keywords: nutritional cobalamin deficiency, abnormal movements, infant