X-linked ichthyosis: Molecular findings in four pedigrees with inconspicuous clinical manifestations

X-linked ichthyosis (XLI) is the second most common type of ichthyosis, which is characterized by wide and symmetric distribution of adherent, dry, and polygonal scales on the skin. Steroid sulfatase (STS) gene, which is located at chromosome Xp22.31, has been identified as the pathogenic gene of XLI.

In this study, chromosome karyotype analysis, bacterial artificial chromosomes-on-Beads™ (BoBs) assay, fluorescence in situ hybridization (FISH), and single nucleotide polymorphism array (SNP-array) were employed for the prenatal diagnoses in three pregnant women with high-risk serological screening results and a pregnant woman with mental retardation.

STS deletion was identified at chromosome Xp22.31 in all four fetuses. Postnatal follow-up confirmed the diagnosis of ichthyosis in two male fetuses and revealed normal dermatological manifestations in other two female fetuses carrying ichthyosis.

The results of the present study demonstrate that a combination of karyotypying, prenatal BoBs, FISH, and SNP-array may avoid the missed detection of common microdeletions and ensure the accuracy of the detection results, which provides a feasible tool for the reliable etiological diagnosis and better genetic counseling of XLI.