title: Suggestive association with ocular phoria at chromosome 6p22.
abstract: OBJECTIVE
  We conducted a genome-wide association study to identify genetic factors that contribute to the etiology of heterophoria.
  
  
  METHODS
  We measured near and far vertical and horizontal phorias in 988 healthy adults aged 16 to 40 using the Keystone telebinocular with plates 5218 and 5219. We regressed degree of phoria against genotype at 642758 genetic loci. To control for false positives, we applied the conservative genome-wide permutation test to our data.
  
  
  RESULTS
  A locus at 6p22.2 was found to be associated with the degree of near horizontal phoria (P = 2.3 × 10(-8)). The P value resulting from a genome-wide permutation test was 0.014.
  
  
  CONCLUSIONS
  The strongest association signal arose from an intronic region of the gene ALDH5A1, which encodes the mitochondrial enzyme succinic semialdehyde dehydrogenase (SSADH), an enzyme involved in γ-aminobutyric acid metabolism. Succinic semialdehyde dehydrogenase deficiency, resulting from mutations of ALDH5A1, causes a variety of neural and behavioral abnormalities, including strabismus. Variation in ALDH5A1 is likely to contribute to degree of horizontal phoria.
authors: Department of Psychology, University of Cambridge, Cambridge, United Kingdom.
authors: Jenny M
authors: JM
authors: Bosten
authors: Ruth E
authors: RE
authors: Hogg
authors: Gary
authors: G
authors: Bargary
authors: Patrick T
authors: PT
authors: Goodbourn
authors: Adam J
authors: AJ
authors: Lawrance-Owen
authors: John D
authors: JD
authors: Mollon
mesh_terms: D000293:Adolescent; D000328:Adult; D002896:Chromosomes, Human, Pair 6 / Q000235:genetics*; D004247:DNA / Q000235:genetics*; D004252:DNA Mutational Analysis; D005133:Eye Movements; D005260:Female; D055106:Genome-Wide Association Study; D005838:Genotype; D006801:Humans; D008297:Male; D009154:Mutation; D013285:Strabismus / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D050644:Succinate-Semialdehyde Dehydrogenase / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D055815:Young Adult
chemical_list: D004247:DNA; C493643:ALDH5A1 protein, human; D050644:Succinate-Semialdehyde Dehydrogenase
keywords: ALDH5A1; GWAS; SSADH; phoria; strabismus