Deletion of distal promoter of VCXA in a patient with X-linked ichthyosis associated with borderline mental retardation

SummaryBackgroundX-linked ichthyosis (XLI) is caused by deficiency of steroid sulfatase (STS) activity. About 90% XLI patients have large deletions involving the entire STS gene and flanking regions. Recently, VCXA, which is located approximately 0.7 Mb telomeric to the STS gene, was reported as a candidate gene for mental retardation (MR) in patients with XLI.ObjectiveTo delineate the X-chromosomal deletion of a XLI patient with borderline mental retardation.MethodsWe carried out FISH analysis to show that the whole STS gene is deleted, and PCR analysis for fine-scale deletion mapping.ResultsThe deleted segment is approximately 1.6 Mb in size, and includes the entire STS and VCXB1 genes. VCXA itself is intact, but its promoter is deleted.ConclusionA deletion that includes the VCXA promoter is associated with borderline mental retardation in a patient with XLI.