Consistent with this mechanism, we found that the combined frequency of the heterozygous and rare homozygous TLR4 genotypes was low in infants without BPD (1.2%) compared to the term-born infants or to previous reports in pediatric cohorts [15], [16], [26], which may imply a protective role of against BPD in some populations of at-risk preterm infants. The gene discussed is TLR4; the disease is bronchopulmonary dysplasia.