Two Novel and Three Recurrent Mutations in the Mevalonate Pathway Genes in Chinese Patients with Porokeratosis.

Purpose: Porokeratosis (PK) is a chronic autosomal-dominant cutaneous keratinization disorder exhibiting clinical and genetic heterogeneity. Mevalonate decarboxylase (MVD), farnesyl diphosphate synthase (FDPS), phosphomevalonate kinase(PMVK), and mevalonate kinase genes(MVK), which encode the mevalonate pathway, are disease-causing genes in PK. Patients and Methods: Data and blood samples were collected from two Chinese families and five sporadic patients with porokeratosis. Whole-exome and Sanger sequencing were performed to detect pathogenic gene mutation in the patients. Results: Five heterozygous mutations were identified, including a novel FDPS stop-gain mutation c.438T>G (p.Tyr146Ter), a novel MVD missense mutation c.683G>C (p.R228P), and three previously reported MVD mutations: c.746T>C (p.F249S), c.875A>G (p.N292S), and c.1111_1113del (p.371_371del). The novel FDPS c.438T>G mutation was predicted as "disease-causing" (p = 1) by Mutation Taster. The other novel MVD c.683G>C was also predicted as "deleterious" (score = 0.00) by Sorting Intolerant From Tolerant (SIFT), "probably damaging" (score = 1) by PolyPhen2, and "disease-causing" (p = 0.999) by Mutation Taster. Conclusion: Our results extended the mutation spectrum of mevalonate pathway genes in porokeratosis and provided useful strategies for a more accurate diagnosis and genetic counseling.

Two Novel and a Recurrent ATP2C1 Mutations in Chinese Population with Hailey-Hailey Disease.

Purpose: Hailey-Hailey disease (HHD), also known as familial benign chronic pemphigus, is a rare autosomal dominant inherited blistering dermatosis. Pathogenic variants in ATP2C1 have been associated with HHD since 2000. This study aimed to identify the mutations in the ATP2C1 gene in two Chinese pedigrees and two sporadic cases with HHD. Patients and Methods: Two Chinese pedigrees and two sporadic cases were included in this study. Whole-exome sequencing and Sanger sequencing were performed to detect the mutation of the ATP2C1 gene. Predictions of protein structure and function were performed using bioinformatics tools, including Mutation Taster, Polyphen-2, SIFT, and Swiss-Model. Results: In this study, we detected three heterozygous mutations, including novel compound mutations of (c.1840-4delA and c.1840_1844delGTTGC), splice site mutation of c.1570+3A>C, and a previously known nonsense mutation c.1402C>T in the ATP2C1 gene. Combined with our previous study, ten patients with c.1402C>T mutation in the ATP2C1 gene have been identified, and all these patients originated from Jiangxi Province. Conclusion: c.1402C>T mutation in the ATP2C1 gene was considered a regional highly prevalent mutation in the Chinese population with HHD. The results added new variants to the database of ATP2C1 mutations associated with HHD.

A new POLH mutation in a consanguineous Chinese family with xeroderma pigmentosum variant type.

We report a Chinese consanguineous family with a variant type of xeroderma pigmentosum (XPV), and identified one novel mutation in the patient. Our study expands the mutational spectrum of XPV. Click here for the corresponding questions to this CME article.