Genome-Wide Significance and Replication of the Chromosome 12p11.22 Locus Near the PTHLH Gene for Peripartum Cardiomyopathy

BACKGROUND: Peripartum (PP) cardiomyopathy (CM) is a rare condition of unknown etiology that occurs in late pregnancy or early postpartum. Initial evidence suggests that genetic factors may influence PPCM. This study evaluated and replicated genome-wide association of single nucleotide polymorphisms with PPCM. METHODS AND RESULTS: Genome-wide single nucleotide polymorphisms in women with verified PPCM diagnosis (n=41) were compared separately with local control subjects (n=49 postmenopausal age-discordant women with parity ≥1 and no heart failure) and iControls (n=654 women ages 30 to 84 years with unknown phenotypes). A replication study of independent population samples used new cases (PPCM2, n=30) compared with new age-discordant control subjects (local2, n=124) and with younger control subjects (n=89) and obstetric control subjects (n=90). A third case set of pregnancy-associated CM cases not meeting strict PPCM definitions (n=29) was also studied. In the genome-wide association study, 1 single nucleotide polymorphism (rs258415) met genome-wide significance for PPCM versus local control subjects (P=2.06×10(-8); odds ratio OR, 5.96). This was verified versus iControls (P=7.92×10(-19); OR, 8.52). In the replication study for PPCM2 cases, rs258415 (ORs are per C allele) replicated at P=0.009 versus local2 control subjects (OR, 2.26). This replication was verified for PPCM2 versus younger control subjects (P=0.029; OR, 2.15) and versus obstetric control subjects (P=0.013; OR, 2.44). In pregnancy-associated cardiomyopathy cases, rs258415 had a similar effect versus local2 control subjects (P=0.06; OR, 1.79), younger control subjects (P=0.14; OR, 1.65), and obstetric control subjects (P=0.038; OR, 1.99). CONCLUSIONS: Genome-wide association with PPCM was discovered and replicated for rs258415 at chromosome 12p11.22 near PTHLH. This study indicates a role of genetic factors in PPCM and provides a new locus for further pathophysiological and clinical investigation.