Abstract：
Phacomatosis pigmentokeratotica (PPK) is a rare epidermal nevus (EN) syndrome, featured by co-occurrence of speckled lentiginous nevus (SLN) and nevus sebaceous (NS). The underlying mechanism has not been clarified. Pathogenic mutations in HRAS, KRAS and BRAF gene are recently recognized as the genetic cause of PPK. Here we present a case of Chinese PPK with a mosaic mutation in HRAS gene. Physical examination of the 4-year-old male proband showed NS locating on the scalp, with EN and SLN on trunk and extremities. Except congenital fundus vascular tortuosity, no evidence of extracutaneous abnormalities was found in this case. A rare heterozygous missense c. 181 C>A mosaic mutation in HRAS was identified in samples from NS, EN and pigmented nevus using next-generation sequencing and Sanger sequencing. Meanwhile, no mutation was found in the non-lesion skin, hair follicle, or blood DNA. Recent breakthrough in clinical manifestation, genetic mutation and prognosis of PPK is also reviewed.
摘要：
色素性角化孔病（PPK）是一种罕见的表皮痣（EN）综合征，特征是斑点淡色痣（SLN）和皮脂腺痣（NS）同时出现。潜在的机制尚未明确。HRAS中的致病突变，KRAS和BRAF基因最近被认为是PPK的遗传原因。在这里，我们介绍了一个在HRAS基因中具有镶嵌突变的中国PPK病例。4岁男性先证者的体格检查显示NS位于头皮上，在躯干和四肢上使用EN和SLN。除了先天性眼底血管弯曲，在这种情况下，没有发现皮外异常的证据。罕见的杂合错义c。在NS的样品中鉴定出HRAS中的181C>A镶嵌突变，EN和色素痣使用下一代测序和Sanger测序。同时,在非病变皮肤中没有发现突变，毛囊,或者血液DNA.最近在临床表现上取得突破，同时对PPK的基因突变和预后进行了综述。
