斑驳病一家系c—kit基因突变检测及共聚焦激光扫描显微镜皮损观察

A family of piebaldism： pathological features observed with confocal laser scanning microscopy in vivo and c-kit gene mutation

目的报告一例斑驳病家系，运用共聚焦激光扫描显微镜对先证者进行实时在体组织学检查和诊断，并检测该家系患者c—kit基因突变位点。方法应用Vivascope1500^TM皮肤在体共聚焦成像系统对患者皮损进行扫描成像和诊断。采集患者及表型正常者静脉血，提取其外周血白细胞DNA，PCR扩增c—kit基因编码区21对外显子，DNA直接测序，确定点突变的位点。结果患者白斑处共聚焦激光扫描成像结果显示基底层几乎无黑素细胞分布，白斑与色素斑交杂区扫描显示基底层及真皮乳头周围黑素细胞呈灶性或区域性聚集。家系中患者c—kit基因均于17号外显子的2362位碱基发生T〉C突变，密码子TGT突变为CGT，导致高度保守区的Cys788Arg（C788R）错义突变。表型正常者及100例正常人对照未见此突变。结论皮肤在体共聚焦激光扫描显微镜具有实时、无创的特点，在斑驳病等色素缺失性疾病中可作为传统组织病理之外可供选择的新型诊断手段。Cys788Arg突变可能为此家系斑驳病的主要原因。

Objective To observe the histopathological features of piebaldism by confocal laser scanning microscopy （CLSM） in vivo and to investigate c-kit gene mutations in a family of piebaldism. Methods CLSM was applied to describe the histopathological features of piebaldism in a family, and DNA was extracted fi＇om the white blood cells of the family members to amplify the 21 coding exons of c-kit gene by PCR. Automated DNA sequencing was performed to determine the mutation sites. Results As shown by CLSM, almost no melanocytes were present in the basal layer of depigmented patches, otherwise, there was a focal or local aggregating of melanocytes at the basal layer and around the dermal papilla in the joint area of hypopigmented and hyperpigmented patches. In all patients, a T2362C mutation was found in the 17th exon of c-kit gene, which induced a change from TGT to CGT at codon 788, and resulted in a missense mutation of Cys788Arg at the highly conserved sites. However, such mutation was detected neither in the healthy family members nor in the normal controls. Conclusions CLSM is a new technique for real-time and non-invasive observation of histopathological features of skin, and can be used as an alternative option for the diagnosis of depigmented diseases. The Cys788Arg mutation may be the main cause of piebaldism in this family.