Physical mapping of the serotonin 5-HT(7) receptor gene (HTR7) to chromosome 10 and pseudogene (HTR7P) to chromosome 12, and testing of linkage disequilibrium between HTR7 and autistic disorder.

The gene encoding the serotonin 5-HT(7) receptor (HTR7) has been considered as a candidate locus in several neuropsychiatric disorders, based on pharmacological evidence and ligand-binding studies. After determining over 3 kb of previously unpublished sequence from introns 1 and 2 of HTR7, a single base (C/T) polymorphism in the second intron of HTR7 was found. Allele-specific PCR was used to genotype the HTR7 marker in 53 trios consisting of subjects with autistic disorder and both parents. Using the transmission disequilibrium test (TDT), no evidence of preferential transmission of either allele was found (TDT chi(2) = 0.252, p = 0.602). Sequence data obtained from both intron 1 and intron 2 of HTR7, and from the 5-HT(7) pseudogene (HTR7P), was used to confirm localization of HTR7 to 10q23 and HTR7P to 12p13 using radiation hybrid analyses.