In 13 out of the 24 (52%) a genetic diagnosis was achieved: PRF1 n = 4 (FHL2), STX11 n = 2 (FHL4), and STXBP2 n = 4 (FHL5), RAB27A n = 2 (Griscelli syndrome type 2), BIRC4 n = 1 (XIAP). This evidence concerns the gene RAB27A and Griscelli syndrome type 2.