Identification of high risk DISC1 protein structural variants in patients with bipolar spectrum disorder.
In a large Scottish pedigree, a balanced translocation t (1;11)(q42.1;q14.3) disrupting the DISC1 and DISC2 genes segregates with major mental illness, including schizophrenia and depression. A frame-shift carboxyl-terminal deletion was reported in DISC1 in an American family with schizophrenia, but subsequently found in two controls. Herein, we test one hypothesis utilizing a large scale case-control mutation analysis: uncommon DISC1 variants are associated with high risk for bipolar spectrum disorder. We have analyzed the regions of likely functional significance in the DISC1 gene in 504 patients with bipolar spectrum disorder and 576 ethnically similar controls. Five patients were heterozygous for ultra-rare protein structural variants not found in the 576 controls (p=0.02, one-sided Fisher's exact test) and shown to be ultra-rare by their absence in a pool of 10,000 control alleles. In our sample, ultra-rare (private) protein structural variants in DISC1 are associated with an estimated attributable risk of about 0.5% in bipolar spectrum disorder. These data are consistent with: (i) the high frequency of depression in the large Scottish family with a translocation disrupting DISC1; (ii) linkage disequilibrium analysis demonstrating haplotypes associated with relatively small increases in risk for bipolar disorder (<3-fold odds ratio). The data illustrate how low/moderate risk haplotypes that might be found by the HapMap project can be followed up by resequencing to identify protein structural variants with high risk, low frequency and of potential clinical utility.
Song
Wenjia
W
Department of Molecular Genetics, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA 91010, United States.
Li
Wenyan
W
Noltner
Katie
K
Yan
Jin
J
Green
Elaine
E
Grozeva
Detelina
D
Jones
Ian R
IR
Craddock
Nick
N
Longmate
Jeff
J
Feng
Jinong
J
Sommer
Steve S
SS
D000328:Adult; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000208:ethnology / Q000235:genetics*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D014644:Genetic Variation / Q000235:genetics*; D006801:Humans; D015810:Linkage Disequilibrium / Q000235:genetics; D008297:Male; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018570:Risk Assessment / Q000379:methods; D012606:Scotland / Q000208:ethnology; D014178:Translocation, Genetic / Q000235:genetics
C412476:DISC1 protein, human; D009419:Nerve Tissue Proteins