A 15-base pair (bp) palindromic insertion associated with a 3-bp deletion in exon 10 of the gp91-phox gene, detected in two patients with X-linked chronic granulomatous disease.

Molecular genetic studies were carried out on two maternal cousins with X-linked chronic granulomatous disease (X-CGD). Sequencing analysis of polymerase chain reaction (PCR)-amplified DNA fragments from both patients revealed a 15-base pair (bp) insertion associated with a 3-bp deletion in exon 10 of the cytochrome b heavy chain (gp91-phox) gene. Results of genomic PCR with primers flanking the insertion/deletion site confirmed the mutation, and also demonstrated that their mothers were carriers for the disease. Palindromic sequences were found in the 15-bp insertion as well as in the flanking 3-bp deletion site, which may play a role in the mechanism of this mutation.