Identifiable causes include the following mutations: 9q21.3‐22, PRF‐1, UNC 13D, STX 11, and STX BP2, Chediak‐Higashi syndrome (CHS‐ 1/LYST), Griscelli syndrome type 2 (RAB 27A), Hermansky‐Pudlak syndrome type 2 (AP3B1), and the X‐linked lymphoproliferative syndromes XLP‐1 (SAP) and XPL‐2 (XIAP) [2]. This evidence concerns the gene LYST and Griscelli disease.