More recently, using 518,230 SNPs, Himes et al. implicated SNPs in phosphodiesterase 4D, cAMP-specific (phosphodiesterase E3 dunce homolog, Drosophila) (PDE4D; OMIM 600129) with risk of asthma in whites from the United States and replicated this finding in two other white populations [7]. This evidence concerns the gene PDE4D and asthma.