Recent adaptive selection at MAOB and ancestral susceptibility to schizophrenia.
The ancestral susceptibility hypothesis has been proposed to explain the existence of susceptibility alleles to common diseases. Some ancestral alleles, reflecting ancient adaptations, may be poorly adapted to the more contemporary environmental conditions giving rise to an increased risk to suffer some common disorders. In order to test this hypothesis in schizophrenia, we focused on the monoamine oxidase B gene (MAOB). This gene is involved in deamination of several monoamines, including both xenobiotic amines present in several foods, as well as neurotransmitters such as dopamine. In addition, preliminary analysis based on phase I HapMap data suggested that recent natural selection has acted on this locus. We further explored the existence of this recent positive selection using a test based on extension of linkage disequilibrium (LD) to large distance at the specific selected haplotype taking data from HapMap phase II, and searched for association of the ancestral haplotypes with schizophrenia in a sample of 532 schizophrenic patients and 597 controls from Spain. Our analysis suggested the existence of a haplotype of MAOB subject to recent selection. In agreement with the ancestral susceptibility hypothesis, the ancestral haplotypes were significantly over-represented in patients (P = 0.047). These haplotypes conferred an increased risk to schizophrenia, restricted to males (P = 0.024, OR = 1.41, 95% CI 1.01-1.90). Thus, pending on replication studies, MAOB seems to fit the ancestral susceptibility model, validating a new strategy to search for common schizophrenia susceptibility genes by focusing in those functional candidate genes subject to recent positive selection.
Fundación Pública Galega de Medicina Xenómica (FPGMX), University of Santiago Hospital Complex, Santiago de Compostela, Spain.
Noa
N
Carrera
Julio
J
Sanjuán
María Dolores
MD
Moltó
Angel
A
Carracedo
Javier
J
Costas
D000483:Alleles; D016022:Case-Control Studies; D002874:Chromosome Mapping; D041321:Chromosomes, Human, X; D015331:Cohort Studies; D016001:Confidence Intervals; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005843:Geography; D006239:Haplotypes; D006720:Homozygote; D006801:Humans; D015810:Linkage Disequilibrium; D008297:Male; D008995:Monoamine Oxidase / Q000235:genetics*; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D012559:Schizophrenia / Q000175:diagnosis / Q000235:genetics*; D012641:Selection, Genetic; D013030:Spain
D008995:Monoamine Oxidase