| Co-Investigator(Kenkyū-buntansha) |
HASHIMOTO Takashi Kurume University School of Medicine, Department of Dermatology, Professor, 医学部, 教授 (20129597)
SUZUMORI Kaoru Nagoya City University School of Medicine, Department of Obstetrics and Gynecolo, 医学部, 教授 (80117829)
NISHIKAWA Takeji Keio University School of Medicine, Department of Dermatology, Professor, 医学部, 教授 (50051579)
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| Research Abstract |
Epidermolysis bullosa (EB) encompasses more than twenty subtype conditions with the common characteristic of marked skin fragility and blister formation after seemingly minor or insignificant trauma to the skin. Based on the ultrastructural location of blister formations, EB is divided into three major categories : simplex, junctional and dystrophic type.
In this study, we confirmed that type VII collagen and laminin 5 were found to be specifically absent or markedly reduced in the skin of our Japanese patients with recessive dystrophi EB (RDEB) and lethal Herlitz EB (HJEB). Using genomic DNA from the patients, we amplified responsible gene with PCR, then screened by heteroduplex, and finally identified specific molecular defects present in each family.
Absence of laminin 5 in the HJEB leads to the elucidation of specific mutations in each of the LAMB3, LAMC2 and LAMA3 genes encoding three polypeptide subunit chains, x3 (150 kDa), f3(125 kDa) and y2(100 kDa) [29]. R635X and R42X mutations in LAMB3 gene have been found to be hot spot mutations in European and American patients with HJEB.However, we found R635X and R42X mutations were rare in Japanese counterparts. Instead, W6lOX and Q166X were frequently found in Japanese families with HJEB, and were thus used for their DNA-based PND [9].
Accordingly, DNA-based prenatal diagnosis of EB were introduced for the Japanese patients with RDEB and HJEB.
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