title: Common variations in ALG9 are not associated with bipolar I disorder: a family-based study.
abstract: BACKGROUND
  A mannosyltransferase gene (ALG9, DIBD1) at chromosome band 11q23 was previously identified to be disrupted by a balanced chromosomal translocation t(9;11)(p24;q23) co-segregating with bipolar affective disorder in a small family. Inborn ALG9 deficiency (congenital disorders of glycosylation type IL) is associated with progressive microcephaly, seizures, developmental delay, and hepatomegaly. It is unknown whether common variations of ALG9 predispose to bipolar affective disorder.
  
  
  METHODS
  We tested five polymorphic markers spanning ALG9 (three intragenic and one upstream microsatellite repeats and one common missense variation, V289I (rs10502151) for their association with bipolar I disorder in two pedigree series. The NIMH (National Institute of Mental Health) pedigrees had a total of 166 families showing transmissions to 250 affected offspring, whereas The PITT (The University of Pittsburgh) pedigrees had a total of 129 families showing transmissions to 135 cases. We used transmission disequilibrium test for the association analyses.
  
  
  RESULTS
  We identified three common and distinct haplotypes spanning the ALG9 gene. We found no statistically-significant evidence of transmission disequilibrium of marker alleles or multi-marker haplotypes to the affected offspring with bipolar I disorder.
  
  
  CONCLUSIONS
  These results suggest that common variations in ALG9 do not play a major role in predisposition to bipolar affective disorder.
authors.affiliation: Department of Obstetrics, Gynecology and Reproductive Sciences, The University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA. baysalb@mwri.magee.edu
authors.forename: Bora E
authors.initials: BE
authors.lastname: Baysal
authors.forename: Joan E
authors.initials: JE
authors.lastname: Willett-Brozick
authors.forename: Silviu-Alin
authors.initials: SA
authors.lastname: Bacanu
authors.forename: Sevilla
authors.initials: S
authors.lastname: Detera-Wadleigh
authors.forename: Vishwajit L
authors.initials: VL
authors.lastname: Nimgaonkar