Department of Dermatology, Philipp University of Marburg, Marburg, Germany.
J Am Acad Dermatol. 2010 Jan;62(1):136-138. doi: 10.1016/j.jaad.2008.12.049. Epub 2009 Jul 25.
In autosomal dominant skin disorders, a pronounced mosaic involvement may sometimes be found to be superimposed on the ordinary nonsegmental lesions. Such "type 2 segmental manifestation" reflects loss of heterozygosity occurring at an early developmental stage, giving rise to a cell clone that lacks the corresponding wild-type allele. Here, this genetic concept is applied to an unusual case of plaque-type porokeratosis of Mibelli (PM) as published in 1893 by Vittorio Mibelli in the International Atlas of Rare Skin Diseases. The right forearm and hand of the 21-year-old patient showed a pronounced linear porokeratosis that had developed since the age of 2 years. Moreover, nonsegmental lesions of PM involved both hands and forearms as well as the face and the neck, having first been noticed at the age of 7 years. Two siblings and the father were likewise affected with PM. Hence, Mibelli's case from 1893 meets all of the criteria of a type 2 segmental manifestation of an autosomal dominant skin disorder. Recognizing such cases of superimposed segmental involvement may help elucidate the molecular basis of PM.
在常染色体显性皮肤疾病中，有时会发现明显的镶嵌性受累叠加在普通的非节段性病变之上。这种“2 型节段性表现”反映了早期发育阶段发生的杂合性丢失，导致缺乏相应野生型等位基因的细胞克隆。在此，将这一遗传概念应用于米贝利斑块型汗孔角化症（PM）的一个不寻常病例，该病例于 1893 年由 Vittorio Mibelli 在《国际罕见皮肤病图谱》中发表。这名 21 岁患者的右前臂和手出现明显的线性汗孔角化症，自 2 岁起发病。此外，PM 的非节段性病变累及双手和前臂以及面部和颈部，在 7 岁时首次被发现。两名兄弟姐妹和父亲也同样患有 PM。因此，Mibelli 于 1893 年的病例符合常染色体显性皮肤疾病 2 型节段性表现的所有标准。认识到这种叠加节段性受累的病例可能有助于阐明 PM 的分子基础。
