title: A missense variant (P10L) of the melanopsin (OPN4) gene in seasonal affective disorder.
abstract: BACKGROUND
  Melanopsin, a non-visual photopigment, may play a role in aberrant responses to low winter light levels in Seasonal Affective Disorder (SAD). We hypothesize that functional sequence variation in the melanopsin gene could contribute to increasing the light needed for normal functioning during winter in SAD.
  
  
  METHODS
  Associations between alleles, genotypes, and haplotypes of melanopsin in SAD participants (n=130) were performed relative to controls with no history of psychopathology (n=90).
  
  
  RESULTS
  SAD participants had a higher frequency of the homozygous minor genotype (T/T) for the missense variant rs2675703 (P10L) than controls, compared to the combined frequencies of C/C and C/T. Individuals with the T/T genotype were 5.6 times more likely to be in the SAD group than the control group, and all 7 (5%) of individuals with the T/T genotype at P10L were in the SAD group.
  
  
  CONCLUSIONS
  The study examined only one molecular component of the non-visual light input pathway, and recruitment methods for the comparison groups differed.
  
  
  CONCLUSIONS
  These findings support the hypothesis that melanopsin variants may predispose some individuals to SAD. Characterizing the genetic basis for deficits in the non-visual light input pathway has the potential to define mechanisms underlying the pathological response to light in SAD, which may improve treatment.
authors.affiliation: Graduate Program in Medical Psychology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States.
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Roecklein
authors.forename: Kelly J
authors.initials: KJ
authors.lastname: Rohan
authors.forename: Wallace C
authors.initials: WC
authors.lastname: Duncan
authors.forename: Mark D
authors.initials: MD
authors.lastname: Rollag
authors.forename: Norman E
authors.initials: NE
authors.lastname: Rosenthal
authors.forename: Robert H
authors.initials: RH
authors.lastname: Lipsky
authors.forename: Ignacio
authors.initials: I
authors.lastname: Provencio
mesh_terms: D000328:Adult; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006239:Haplotypes; D006720:Homozygote; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D017299:Rod Opsins / Q000235:genetics*; D016574:Seasonal Affective Disorder / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D000099210:Melanopsin
chemical_list: D017299:Rod Opsins; D000099210:Melanopsin