Chu Ha Thi, Dinh Duong Tung Anh, Le Doanh Huu, Le Thieu Van, Nguyen Binh Bui, Dang Chuc Van, Vu Quang Van
Department of Pediatrics, Haiphong University of Medicine and Pharmacy, Haiphong, Vietnam.
National Hospital of Dermatology and Venereology, Hanoi, Vietnam.
Pediatr Neonatol. 2023 Jul;64(4):405-410. doi: 10.1016/j.pedneo.2022.09.018. Epub 2023 Jan 3.
Pachyonychia congenita (PC) is a group of autosomal dominant disorders caused by mutations in one of five keratin genes (KRT6A, KRT6B, KRT6C, KRT16, or KRT17). PC is an extremely rare condition. To our knowledge, this is the largest genotype-phenotype study of PC in a Vietnamese population to date.
We investigated keratin gene mutations and clinical features of seven Vietnamese children with PC.
The seven Vietnamese patients were from six different families (two patients in the same family) from across Northern, Central, and Southern Vietnam. All children displayed PC symptoms before 1 year of age, but diagnosis was delayed in 4/7 patients. Thick fingernails, thick toenails, oral leukokeratosis, and follicular hyperkeratosis were the most common features recorded by all seven patients. Plantar keratoderma and thick fingernails were the clinical features associated with the most significant effect on daily function. All patients had mutations in KRT6A (PC-K6a) focused on the 1A and 2B domains. We found three distinct types of mutations (K6a R466P, K6a N171K, and K6a N172del). One mutation (N172del) was common to 5/7 (71.4%) of the patients.
Individuals displaying nail dystrophy, oral leukokeratosis, follicular hyperkeratosis, and plantar keratoderma should be referred for genetic testing given the high likelihood of a PC-K6a-related mutation in patients with this constellation of clinical signs.
先天性厚甲症（PC）是一组常染色体显性疾病，由五个角蛋白基因（KRT6A、KRT6B、KRT6C、KRT16或KRT17）之一的突变引起。PC极为罕见。据我们所知，这是迄今为止越南人群中关于PC的最大规模的基因型-表型研究。
我们调查了7名患有PC的越南儿童的角蛋白基因突变和临床特征。
这7名越南患者来自越南北部、中部和南部的6个不同家庭（其中一个家庭有两名患者）。所有儿童在1岁前均出现PC症状，但4/7的患者诊断延迟。厚指甲、厚趾甲、口腔白色角化病和毛囊性角化过度是所有7名患者记录到的最常见特征。掌跖角化病和厚指甲是对日常功能影响最显著的临床特征。所有患者的KRT6A（PC-K6a）基因在1A和2B结构域发生突变。我们发现了三种不同类型的突变（K6a R466P、K6a N171K和K6a N172del）。其中一种突变（N172del）在5/7（71.4%）的患者中常见。
鉴于出现甲营养不良、口腔白色角化病、毛囊性角化过度和掌跖角化病的个体极有可能存在与PC-K6a相关的突变，因此应将这些个体转诊进行基因检测。
