The high frequency of the SNP in European groups compared to African populations may be the consequence of selective pressure on TIRAP. However, in view of the complex selective pressure of several infectious diseases including TB, malaria, and bacterial sepsis, each of which may select different variants in TLR signalling, speculation on the reasons for ethnic variation in the genes controlling TLR signalling should await further data on the association of these variants with common childhood diseases in African and Caucasian populations. The gene discussed is TIRAP; the disease is infectious disease.