Familial X-linked Ichthyosis, Steroid Sulfatase Deficiency, Mental Retardation, and Nullisomy for Xp223-pter

Steroid sulfatase (STS)—deficient X-linked ichthyosis was diagnosed in a man with short stature and mental retardation. His generation includes five similarly affected male members. A translocation chromosome is segregating in this Newfoundland kindred. The proband's mother and grandmother have normal skin and are of normal intelligence. From his carrier mother, the proband inherited an X short arm (Xp) to Y long arm (Yq) translocation chromosome, with the entire Y short arm and the X short arm terminal segment deleted (Xp223-pter). His cells are completely deficient in STS activity, confirming assignment of the STS locus to Xp223-pter. Effective management of his ichthyosis included treatment with 6% salicylic acid gel under plastic occlusion and removal of the scales by scrubbing.