Background: The heterogeneity of abnormal patterns of expression of type VII collagen in the skin of Japanese patients with generalized recessive dystrophic epidermolysis bullosa (g-RDEB) remains unclear, and the prenatal diagnosis of this condition has not yet been performed in Asia.
Objective: The present study was performed to clarify patterns of abnormal expression of type VII collagen among Japanese patients with g-RDEB, and to evaluate the first application of prenatal diagnosis for this condition in an Asian country.
Methods and results: Only 2 of 8 Japanese patients with g-RDEB evaluated demonstrated a complete absence of type VII collagen at the skin basement membrane zone when tested with an LH7.2 monoclonal antibody. The other 6 patients revealed present, although diminished, LH7.2 reactivity. The mother of 1 patient who lacked reactivity to the LH7.2 monoclonal antibody sought prenatal diagnosis. Electron microscopy of fetal skin specimens obtained at 19 weeks' gestation showed mature anchoring fibrils with no separation of the dermis and epidermis. Indirect immunofluorescence revealed normal expression of type VII collagen. The fetus was diagnosed as being unaffected, and a normal female infant was delivered at 38 weeks' gestation.
Conclusion: Our findings indicate a lower incidence of the negative expression of LH7.2 epitope in the type VII collagen among Japanese rather than non-Japanese patients with g-RDEB. However, LH7.2 still serves as a reliable diagnostic probe under certain conditions such as the diagnosis and prenatal diagnosis of g-RDEB as in the present case.