Syndromic recessive X-linked ichthyosis (RXLI) refers to the cases of RXLI (see this term) that are associated with extracutaneous manifestations as part of a syndrome.
The prevalence of syndromic RXLI is estimated at 1/50,000-1/150,000. It affects almost exclusively males.
Cutaneous manifestations include generalized hyperkeratosis and scaling of the skin. Non cutaneous manifestations may be corneal opacity, late puberty, cryptorchidism and a higher frequency of testicular cancer. Manifestations due to contiguous gene syndrome include neurological abnormalities such as epilepsy and hyposmia, intellectual deficit and/or short stature. This mechanism can be observed in Kallman syndrome, hypergonadotropic hypogonadism, ocular albinism type 1 (see these terms), or hypertrophic pyloric stenosis.
RLXI is due to mutations in the steroid sulfatase STS gene located on chromosome Xp22.3. STS codes for a lipid hydrolase that participates in the regulation of permeability barrier homeostasis and desquamation. STS mutations result in abnormal desquamation, decreased corneodesmosomal degradation and retention hyperkeratosis. Transmission is X-linked recessive.
Last update: March 2012