PCR diagnosis of X-linked ichthyosis: identification of a novel mutation (E560P) of the steroid sulfatase gene.

X-linked ichthyosis (XLI) is an inherited skin disorder due to deficiency of steroid sulfatase (STS) activity. XLI has been diagnosed by assaying STS activity in placenta or lymphocytes of patients after birth. Most patients have a large deletion of the STS gene, generated by inaccurate recombination at the STS locus. However, point mutations in the STS gene have been reported in some patients with complete STS deficiency. In a new case of STS deficiency, we identified an STS missense mutation, Glu560Pro or E560P. This new point mutation suggests that the C-terminal region of the STS enzyme is important for STS enzymatic function. Hum Mutat 15:296, 2000. Copyright 2000 Wiley-Liss, Inc.