c-kit遺伝子変異を解析しえた新生児発症の皮膚肥満細胞症の2例

・当科で経験した新生児期発症の皮膚肥満細胞症の2例を報告する．

・自験例では，肥満細胞の増殖活性や悪性転換にかかわっていると推測されている，4つのホットスポット領域を含むc-kit遺伝子変異を同定できなかった．

・c-kit遺伝子変異を有する肥満細胞は，発症時期や罹患期間によってclonalityのレベルが異なり，変異の同定率に関与している可能性が推測される．

（「症例のポイント」より）

　

Two newborn cases of cutaneous mastocytosis who undergone c-kit gene mutation analysis

　

Uesugi, Saori1）Chino, Takenao1）Utsunomiya, Natsuko1）Utsunomiya, Akira1）Oyama, Noritaka1）Hasegawa, Minoru1） 1）Department of Dermatology, Faculty of Medical Sciences, University of Fukui

　

Two 5-month-old Japanese infants presented a birth-history of brownish maculo-papules spreading over their entire body. The lesional skin biopsy revealed intense accumulation of mast cells in the upper dermis, all of these were positive for tyrosine kinase receptor KIT on immunohistochemistry, suggestive of urticaria pigmentosa. We performed mutation analysis for c-kit gene by direct sequencing using genomic DNA from paraffin-embedded skin samples, to check the four distinct hot spot missense mutations, codons 816, 560, 820, and 839. No mutations were detectable in both cases. We discussed the perspective association between c-kit gene mutation and disease phenotypes, as well as clinical courses and outcome, in cutaneous mastocytosis.