Two siblings with lethal pneumococcal meningitis in a family with a mutation in Interleukin-1 receptor-associated kinase 4.

We describe two siblings with one confirmed and one inferred homozygous base pair deletion in the gene for interleukin-1-related kinase 4 (IRAK-4) who died of pneumococcal meningitis at 2 and 14 months, respectively. Interleukin-1-related kinase 4 deficiency is a potentially lethal immunodeficiency characterized by a poor inflammatory response to pyogenic infections.