Abetalipoproteinemia presenting as severe vitamin K deficiency

Vitamin K deficiency has occasionally been observed in infants after the immediate neonatal period when one or more of the following features is present: diet consisting entirely of breast milk, failure to receive prophylactic vitamin K shortly after birth, therapy with broad-spectrum antibiotics, or chronic diarrhea accompanying malabsorption due to cystic fibrosis or to various acquired causes. This report describes for the first time an infant with the uncommon autosomal recessive disorder abetalipoproteinemia whose major presenting manifestation in early infancy was hemorrhage due to vitamin K deficiency.