No association between oxytocin or prolactin gene variants and childhood-onset mood disorders

Background: Oxytocin (OXT) and prolactin (PRL) are neuropeptide hormones that interact with the serotonin system and are involved in the stress response and social affiliation. In human studies, serum OXT and PRL levels have been associated with depression and related phenotypes. Our purpose was to determine if single nucleotide polymorphisms (SNPs) at the loci for OXT, PRL and their receptors, OXTR and PRLR, were associated with childhood-onset mood disorders (COMD). Methods: Using 678 families in a family-based association design, we genotyped 16 SNPs at OXT, PRL, OXTR and PRLR to test for association with COMD. Results: No significant associations were found for SNPs in the OXTR, PRL, or PRLR genes. Two of three SNPs 3' of the OXT gene were associated with COMD (p <= 0.02), significant after spectral decomposition, but were not significant after additionally correcting for the number of genes tested. Supplementary analyses of parent-of-origin and proband sex effects for OXT SNPs by Fisher's Exact test were not significant after Bonferroni correction. Conclusions: We have examined 16 OXT and PRL system gene variants, with no evidence of statistically significant association after correction for multiple tests. (C) 2010 Elsevier Ltd. All rights reserved.