title: B12 deficiency is common in infants and is accompanied by serious neurological symptoms.
abstract: OBJECTIVE
  Adverse neurological symptoms have been linked to vitamin B12 deficiency in infants. This explorative study described the clinical presentation associated with vitamin B12 deficiency in this age group.
  
  
  METHODS
  The study comprised infants who were born between 2004 and 2012 and were tested for vitamin B12 levels after they were admitted to a hospital with neurological symptoms at less than one year of age. Vitamin B12 deficiency was defined as low cobalamin in serum and/or increased homocysteine and/or increased methylmalonate. It was diagnosed according to the applicable International Classification of Diseases, 10th revision, and recorded as vitamin B12 deficiency in the medical records. All information was retrieved from medical records and compared to symptomatic infants with normal levels.
  
  
  RESULTS
  Of the 121 infants tested, 35 had vitamin B12 deficiency and 86 had normal levels. Vitamin B12 deficiency was diagnosed at an average age of 1.7 months and was more common among boys. Seizures and apparent life-threatening events were the most common symptoms among infants with B12 deficiency compared to infants with normal levels.
  
  
  CONCLUSIONS
  Vitamin B12 deficiency was more common in infants than we expected and presented with severe symptoms, such as seizures and apparent life-threatening events.
authors.affiliation: Unit of Research, Education and Development, Östersund Hospital, Östersund, Sweden.
authors.forename: T
authors.initials: T
authors.lastname: Irevall
authors.affiliation: Unit of Research, Education and Development, Östersund Hospital, Östersund, Sweden.
authors.forename: I
authors.initials: I
authors.lastname: Axelsson
authors.affiliation: Unit of Research, Education and Development, Östersund Hospital, Östersund, Sweden.|Department of Clinical Science, Paediatrics, Umeå University, Umeå, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Naumburg
mesh_terms: D057768:Brief, Resolved, Unexplained Event / Q000209:etiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012189:Retrospective Studies; D012640:Seizures / Q000209:etiology*; D013548:Sweden / Q000453:epidemiology; D014806:Vitamin B 12 Deficiency / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology
keywords: Apparent life-threatening event; Infant nutrition; Neurological symptoms; Seizures; Vitamin B12 deficiency