title: Outcome of individuals with low-moderate methylmalonic aciduria detected through a neonatal screening program.
abstract: BACKGROUND
  The clinical spectrum of methylmalonic aciduria (MMAuria) ranges from severe, neonatal acidosis to benign asymptomatic organic aciduria. In 1975, screening for MMAuria was established in the province of Quebec. Although newborn screening programs facilitate presymptomatic detection and treatment and also detect asymptomatic variants, uncertainties about potential long-term hazards of mild to moderate elevations of MMA create concern. The objective of this study was to examine the outcome of individuals excreting low to intermediate quantities of MMA, ascertained by a newborn screening program.
  One hundred and thirty-six individuals with elevations of urinary MMA were initially identified by the screening program; 122 individuals were noted to have excretion of urinary MMA <1400 micromol/mmol creatinine. At follow-up assessment at 1 year of age, in 65 of these 122 individuals, the MMA excretion had resolved. Of the remaining individuals, 9 were lost to follow-up, 13 had symptoms, and the remaining 35 were free of symptoms. Among the 35 individuals with asymptomatic persistent MMAuria, MMA excretion has resolved in 13 over 1 year; 22 individuals exhibit persistent low-moderate MMAuria (range, 210 to 1133 micromol/mmol creatinine).
  
  
  CONCLUSIONS
  Follow-up examination of individuals in the latter asymptomatic cohort with persistent low-moderate MMAuria indicates normal somatic and cognitive outcomes.
authors.affiliation: C. R. Scriver Biochemical Genetics Unit, Montreal; Children's Hospital, Montreal; Service of Medical Genetics, Department of Pediatrics, Ste-Justine Hospital, Montreal, Canada.
authors.forename: L C
authors.initials: LC
authors.lastname: Sniderman
authors.forename: M
authors.initials: M
authors.lastname: Lambert
authors.forename: R
authors.initials: R
authors.lastname: Giguère
authors.forename: C
authors.initials: C
authors.lastname: Auray-Blais
authors.forename: B
authors.initials: B
authors.lastname: Lemieux
authors.forename: R
authors.initials: R
authors.lastname: Laframboise
authors.forename: D S
authors.initials: DS
authors.lastname: Rosenblatt
authors.forename: E P
authors.initials: EP
authors.lastname: Treacy
mesh_terms: D000293:Adolescent; D000328:Adult; D000592:Amino Acid Metabolism, Inborn Errors / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D005347:Fibroblasts / Q000378:metabolism; D005500:Follow-Up Studies; D017408:Guidelines as Topic; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008764:Methylmalonic Acid / Q000652:urine*; D015997:Neonatal Screening; D010641:Phenotype; D010808:Physical Examination; D011379:Prognosis; D011581:Psychological Tests
chemical_list: D008764:Methylmalonic Acid