Skin Diseases: DNA-Based Diagnoses and Prenatal Diagnoses

Among a range of inherited skin disorders, some of markedly severe phenotypes have been widely considered as indications for prenatal diagnoses. Recent studies have achieved significant progress in understanding the molecular basis of these heritable skin discases. These include epidermolysis bullosa (EB). a group ef mechanobullous genodermatoses, ichthyosis, a heterogeneous condition of gcneralized hyperkcratosis, and oculocutaneous albinism, in which an abnormal melanin synthcsis in the skin and eyes is a hallmark. The responsible gene for Lhe dystrophic forms of EB has been identified as a gene encoding type VII collagcn, l'or lethal Herlit7, EB the genes encoding the a3, fi3. or 72 chain of laminin 5, for pyloric-atresia juctional EB syndrome the genes encoding the or6 or ti4 integrins, and for tyrosinase negative oculocutaneous albinism the tyrosinase gene, Specific mutations in thc responsible gene or genes have implications for understanding the structure-functlon reiationship and phenotypelgenotype correlation of each disorder, and also provide the busis for DNA-based diagnoses as well as prenatal diagnoses for families at risk of a recurrence of the disease, Furthermore. understanding the genetic basis of each inherited skin digease sets thc stage for gene therapy approaches for the treatinent of the rcspective condition. Ke.y words: prenatal diagnosis, epidermelysis bul]osa, albinism, ichthyosis, fetal skin