title: Nutritional vitamin B12 deficiency: two cases detected by routine newborn urinary screening.
abstract: We describe two asymptomatic newborns with nutritional vitamin B12 deficiency in whom increased urinary methylmalonic acid was detected by routine neonatal screening at 3 weeks of age. Both infants were exclusively breast-fed. One mother suffered from pernicious anaemia, and the other was a strict vegetarian. Both mothers had no clinical or haematological abnormality, aside from a borderline mean corpuscular volume for the vegetarian mother. This report illustrates the early appearance of functional vitamin B12 deficiency in breast-fed infants of vitamin B12-depleted mothers. It also demonstrates that urinary methylmalonic acid measurement is a sensitive indicator of tissue vitamin B12 deficiency.
authors.affiliation: Department of Paediatrics, Hôpital Sainte-Justine, Côte Ste-Catherine, Montréal, Québec, Canada.
authors.forename: J L
authors.initials: JL
authors.lastname: Michaud
authors.forename: B
authors.initials: B
authors.lastname: Lemieux
authors.forename: H
authors.initials: H
authors.lastname: Ogier
authors.forename: M A
authors.initials: MA
authors.lastname: Lambert
mesh_terms: D001942:Breast Feeding; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008764:Methylmalonic Acid / Q000652:urine*; D009035:Mothers; D015997:Neonatal Screening; D014805:Vitamin B 12 / Q000627:therapeutic use; D014806:Vitamin B 12 Deficiency / Q000175:diagnosis / Q000188:drug therapy / Q000652:urine*
chemical_list: D008764:Methylmalonic Acid; D014805:Vitamin B 12