Ichthyosis follicularis, alopecia, and photophobia (IFAP) syndrome due to mutation of the gene MBTPS2 in a large Australian kindred.

Ichthyosis follicularis, alopecia and photophobia (IFAP) is a rare genodermatosis. Most patients have been men without significant family history. We present the largest kindred of IFAP reported to date in the medical literature clearly demonstrating X-linked inheritance. The gene defect has recently been mapped to Xp22.11-p22.13. Missense mutations of the gene, MBTPS2, which codes for an intramembrane zinc metalloprotease essential for cholesterol homeostasis and endoplasmic reticulum stress response, are associated with the IFAP phenotype in this kindred. We describe the clinical features and discuss the differential diagnosis of IFAP. Our proband has benefited from treatment with acitretin.