Observations
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.

Conclusions
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.

(Arch Dermatol. 1993;129:1455-1459)