DNA-based prenatal diagnosis of heritable skin diseases

Recent success in identifying candidate genes and demonstrating mutations in such genes has set the stage for DNA-based prenatal diagnosis of genodermatoses. An example of such conditions is epidermolysis bullosa in which discrete mutations have been identified in different forms of the disease. The severity of the clinical phenotype in some forms of epidermolysis bullosa appears to justify prenatal diagnosis in families at risk for recurrence of the disease.

DNA-based prenatal diagnosis can be performed on chorionic villi, which can be obtained as early as the eighth week of gestation. Thus, the approaches that use sensitive and specific molecular probes will allow identification of a fetus at risk relatively early during the pregnancy. Such prenatal diagnosis has successfully been performed in families with recessive dystrophic epidermolysis bullosa using type VII collagen-specific markers.

Combination of informative intragenic and flanking DNA markers, and eventual identification of specific mutations in additional families with recessive dystrophic epidermolysis bullosa, is expected to allow early prenatal diagnosis in most families at risk for this devastating skin disease. An emerging technology in the field of prenatal genetics involves blastomere analysis prior to implantation. These DNA-based technologies will undoubtedly replace invasive skin biopsy in cases where candidate genes or specific mutations have been identified. Finally, identification of specific mutations will provide the foundation for potential gene replacement therapy in individuals affected with severe skin diseases.