Evidence for HTR1A and LHPP as interacting genetic risk factors in major depression.

The HTR1A −1019C>G genotype was associated with major depression in the Utah population. Linkage analysis on Utah pedigrees with strong family histories of major depression including only cases with the HTR1A −1019G allele revealed a linkage peak on chromosome 10 (maximum HLOD=4.4). Sequencing of all known genes in the linkage region revealed disease-segregating single-nucleotide polymorphisms (SNPs) in LHPP. LHPP SNPs were also associated with major depression in both Utah and Ashkenazi populations. Consistent with the linkage evidence, LHPP associations depended on HTR1A genotype. Lhpp or a product of a collinear brain-specific transcript, therefore, may interact with Htr1a in the pathogenesis of major depression.