A 14-month-old infant exclusively breastfed by a vegan mother presents with hypotonia, developmental regression, pallor, and a large tongue. CBC shows macrocytic anemia (MCV 112 fL). Serum B12 is 68 pg/mL (normal >200). Homocysteine is markedly elevated. What is the explanation for B12 deficiency in this breastfed infant?
- A Congenital pernicious anemia in the infant
- B Intestinal malabsorption due to celiac disease
- C Maternal B12 deficiency transmitted through breast milk ✓
- D Transcobalamin II deficiency (genetic)
Correct answer: C. Maternal B12 deficiency transmitted through breast milk
Explanation
Breastfed infants of vegan or vegetarian mothers who do not supplement with B12 are at high risk of B12 deficiency because human breast milk B12 content directly reflects maternal serum B12. Neurological manifestations including developmental regression, hypotonia, and irritability may precede or occur without obvious hematological changes. Elevated homocysteine (a sensitive marker) confirms functional B12 deficiency. Early detection and supplementation can reverse neurological damage; delayed treatment may lead to permanent cognitive impairment.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.