USB1 and neutropenia: For instance, two Ethiopian siblings initially misdiagnosed with xeroderma pigmentosum were found to carry a homozygous pathogenic variant in the USB1 gene (c.682C>T; p.Gln228*) and a novel heterozygous mutation in CSF3R (g.160C>T; p.His54Tyr), suggesting an atypical presentation of poikiloderma with neutropenia [26].