An Infant Refugee with Anemia and Low Serum Vitamin B12

An infant with a history of hypotonia, developmental delay, and inadequate nutrition was evaluated. The patient was the offspring of a consanguineous (first cousin) Syrian couple, born at term in Syria after an unremarkable pregnancy. His neonatal course was unremarkable. At the age of 7 months he presented with intermittent diarrhea, fever, and poor feeding. His symptoms progressed, and at 11 months (upon migration to Canada) he was admitted to the hospital for weight loss, decreased urine output, fever, and the loss of skills such as babbling, rolling over, or sitting without support. At the time of admission, he was only taking maternal breast milk.On physical examination, he was pale and irritable. There were no dysmorphic features. He had limited antigravity movements, hepatomegaly, and a systolic ejection murmur. His initial chemistry and hematology evaluation included hemoglobin level of 45 g/L (reference interval, 100–140 g/L), with moderate microcytosis and macrocytosis, mild polychromasia, and schistocytes. His reticulocyte count was 168 × 109/L (reference interval, 10–100 × 109/L). Plasma vitamin B12 was 23 μmol/L). A nasopharyngeal swab was positive for rhinovirus.Metabolic studies were obtained (Table 1). The total and free carnitine concentrations were normal. Urine organic acids identified an increased methylmalonate peak of u003e200 mmol/mol creatinine (reference interval, 0.58–3.56 mmol/mol creatinine), and his acylcarnitine profile included increased propionylcarnitine of 2.26 μmol/L (reference interval, u003c1.08 μmol/L). The total plasma homocysteine (Hcy) was increased at 239 μmol/L (reference interval, 2.9–10 μmol/L). Methionine concentration in plasma was normal at 25 μmol/L (reference interval, 3–29 μmol/L), and the cystine concentration was 1 μmol/L (reference interval, 23–68 μmol/L).View this table:Table 1. Patient values and patterns seen typically with select disorders. QUESTIONS TO CONSIDER1. What potential disorders are suggested by the increases in serum …