Variable skin findings in two siblings with KDSR mutations manifesting in PERIOPTER syndrome.

Pathogenic variants in the KDSR gene give rise to a Mendelian disorder called PERIOPTER syndrome. The disease is caused by a disruption in ceramide synthesis, with an impact on both skin and bone marrow. Patients with PERIOPTER syndrome show intermittent thrombocytopenia and/or associated anemia as well as disorders of keratinization. We present two siblings with identical compound heterozygous pathogenic variants in the KDSR gene, but with different clinical manifestations.