IL-18R1 and IL-18RAP SNPs may be associated with bronchopulmonary dysplasia in African-American infants

INTRODUCTION: The genetic contribution to the development of bronchopulmonary dysplasia (BPD) in prematurely born infants is substantial, but information related to the specific genes involved is lacking. RESULTS: Genotype analysis revealed, after multiple comparisons correction, two significant single-nucleotide polymorphisms (SNPs), rs3771150 (IL-18RAP) and rs3771171 (IL-18R1), in African Americans (AAs) with BPD (vs. AAs without BPD; q < 0.05). No associations with Caucasian (CA) BPD, AA or CA respiratory distress syndrome (RDS), or prematurity in either AAs or CAs were identified with these SNPs. Respective frequencies were 0.098 and 0.093 in infants without BPD and 0.38 for each SNP in infants with BPD. In the replication set (82 cases; 102 controls), the P values were 0.012 for rs3771150 and 0.07 for rs3771171. Combining P values using Fisher's method, overall P values were 8.31 x 10(-7) for rs3771150 and 6.33 x 10(-6) for rs3771171. DISCUSSION: We conclude that IL-18RAP and IL-18R1 SNPs identify AA infants at risk for BPD. These genes may contribute to AA BPD pathogenesis via inflammatory-mediated processes and require further study. METHODS: We conducted a case-control SNP association study of candidate genes (n = 601) or 6,324 SNPs in 1,091 prematurely born infants with gestational age < 35 weeks, with or without neonatal lung disease including BPD. BPD was defined as a need for oxygen at 28 days.