Summary

Vitamin B₁₂ or cobalamin deficiency, a rare clinical entity in pediatric age, is found most exclusively in breastfed infants, whose mothers are strictly vegetarian non-supplemented or with pernicious anaemia. In this article, the authors describe a 10-month-old infant admitted for vomiting, refusal to eat and prostration. The infant was exclusively breastfed and difficulties in introduction of new foods were reported. Failure to thrive since 5 months of age was also noticed. Laboratory evaluation revealed severe normocytic normochromic anaemia and cobalamin deficit. A diagnosis of α-thalassemia trait was also made. Maternal investigation showed autoimmune pernicious anaemia. This case shows the severity of vitamin B₁₂ deficiency and the importance of adopting adequate and precocious measures in order to prevent potentially irreversible neurologic damage.