Pei-Guang Wang

Genome-wide association study in a Chinese Han population identifies nine new susceptibility loci for systemic lupus erythematosus

We performed a genome-wide association study (GWAS) of systemic lupus erythematosus (SLE) in a Chinese Han population by genotyping 1,047 cases and 1,205 controls using Illumina Human610-Quad BeadChips and replicating 78 SNPs in two additional cohorts (3,152 cases and 7,050 controls). We identified nine new susceptibility loci (ETS1, IKZF1, RASGRP3, SLC15A4, TNIP1, 7q11.23, 10q11.22, 11q23.3 and 16p11.2; 1.77 × 10−25 ≤ Pcombined ≤ 2.77 × 10−8) and confirmed seven previously reported loci (BLK, IRF5, STAT4, TNFAIP3, TNFSF4, 6q21 and 22q11.21; 5.17 × 10−42 ≤ Pcombined ≤ 5.18 × 10−12). Comparison with previous GWAS findings highlighted the genetic heterogeneity of SLE susceptibility between Chinese Han and European populations. This study not only advances our understanding of the genetic basis of SLE but also highlights the value of performing GWAS in diverse ancestral populations.

Association analyses identify six new psoriasis susceptibility loci in the Chinese population

We extended our previous genome-wide association study for psoriasis with a multistage replication study including 8,312 individuals with psoriasis (cases) and 12,919 controls from China as well as 3,293 cases and 4,188 controls from Germany and the United States and 254 nuclear families from the United States. We identified six new susceptibility loci associated with psoriasis in the Chinese study containing the candidate genes ERAP1, PTTG1, CSMD1, GJB2, SERPINB8 and ZNF816A (combined P < 5 × 10−8) and replicated one locus, 5q33.1 (TNIP1-ANXA6), previously reported (combined P = 3.8 × 10−21) in the European studies. Two of these loci showed evidence for association in the German study at ZNF816A and GJB2 with P = 3.6 × 10−3 and P = 7.9 × 10−3, respectively. ERAP1 and ZNF816A were associated with type 1 (early onset) psoriasis in the Chinese Han population (test for heterogeneity P = 6.5 × 10−3 and P = 1.5 × 10−3, respectively). Comparisons with the results of previous GWAS of psoriasis highlight the heterogeneity of disease susceptibility between the Chinese and European populations. Our study identifies new genetic susceptibility factors and suggests new biological pathways in psoriasis.

Exome sequencing identifies MVK mutations in disseminated superficial actinic porokeratosis

Disseminated superficial actinic porokeratosis (DSAP) is an autosomal dominantly inherited epidermal keratinization disorder whose etiology remains unclear. We performed exome sequencing in one unaffected and two affected individuals from a DSAP family. The mevalonate kinase gene (MVK) emerged as the only candidate gene located in previously defined linkage regions after filtering against existing SNP databases, eight HapMap exomes and 1000 Genomes Project data and taking into consideration the functional implications of the mutations. Sanger sequencing in 57 individuals with familial DSAP and 25 individuals with sporadic DSAP identified MVK mutations in 33% and 16% of these individuals (cases), respectively. All 14 MVK mutations identified in our study were absent in 676 individuals without DSAP. Our functional studies in cultured primary keratinocytes suggest that MVK has a role in regulating calcium-induced keratinocyte differentiation and could protect keratinocytes from apoptosis induced by type A ultraviolet radiation. Our results should help advance the understanding of DSAP pathogenesis.

Deep sequencing of the MHC region in the Chinese population contributes to studies of complex disease

The human major histocompatibility complex (MHC) region has been shown to be associated with numerous diseases. However, it remains a challenge to pinpoint the causal variants for these associations because of the extreme complexity of the region. We thus sequenced the entire 5-Mb MHC region in 20,635 individuals of Han Chinese ancestry (10,689 controls and 9,946 patients with psoriasis) and constructed a Han-MHC database that includes both variants and HLA gene typing results of high accuracy. We further identified multiple independent new susceptibility loci in HLA-C, HLA-B, HLA-DPB1 and BTNL2 and an intergenic variant, rs118179173, associated with psoriasis and confirmed the well-established risk allele HLA-C*06:02. We anticipate that our Han-MHC reference panel built by deep sequencing of a large number of samples will serve as a useful tool for investigating the role of the MHC region in a variety of diseases and thus advance understanding of the pathogenesis of these disorders.

Genetic heterogeneity in acrokeratosis verruciformis of Hopf.

Background.  Acrokeratosis verruciformis of Hopf (AKV) is a rare genodermatosis characterized by multiple flat‐topped, flesh‐coloured papules on the dorsa of hands and feet, and punctuate keratoses on the palms and soles. A mutation in the ATP2A2 gene has been shown to be associated with AKV and with Dariers disease (DD).

The familial risk of acne vulgaris in Chinese Hans – a case‐control study

Background  Acne is a chronic inflammatory disease of the pilosebaceous follicles. Recent studies bring us increasing evidences that hereditary factors play an important but indirect role in acne.

Association of HLA-DQA1 and DQB1 alleles with keloids in Chinese Hans

BACKGROUND Some studies have suggested that human HLA status might potentiate development of keloids phenotype, and exists ethnic differences. No report has been published about HLA-DQA1 and DQB1 alleles associated with keloids in Chinese Hans. OBJECTIVES To investigate whether HLA-DQA1 and DQB1 alleles are associated with genetic susceptibility to keloids in Chinese Hans. METHODS Polymerase chain reaction-sequence-specific primer (PCR-SSP) method was used to analyze the distribution of HLA-DQA1 and DQB1 alleles among 192 patients with keloids and 273 healthy controls in Chinese Hans. RESULTS (1) The frequencies of HLA-DQA1*0104, DQB1*0501 and DQB1*0503 (OR = 2.13, P(c) = 0.0063; OR = 14.42, P(c) < 10(-7) and OR = 6.09, P(c) < 10(-7), respectively) were significantly higher, while the frequencies of DQA1*0501, DQB1*0201 and DQB1*0402 (OR = 0.46, P(c) = 0.0099; OR = 0.24, P(c) < 10(-4) and OR = 0.10, P(c)=0.0054, respectively) were lower in patients than in controls. (2) In this study significant susceptibility haplotypes to keloids were DQA1*0104-DQB1*0501 and DQA1*0104-DQB1*0503. (3) HLA-DQB1*0501 and DQB1*0503 were positively associated with all subgroups of keloid patients. However, the DQA1*0104 (OR = 2.51, P(c) = 0.0009; OR = 2.22, P(c) = 0.0090 and OR = 2.20, P(c) = 0.0117, respectively) was only prevalent in keloid patients with single site, moderate severity and negative family history. (4) HLA-DQB1*0201 (OR = 0.27, P(c) = 0.0018 and OR = 0.27, P(c) = 0.0012, respectively) and DQB1*0402 (OR = 0.07, P(c) = 0.0270 and OR = 0.07, P(c) = 0.0306, respectively) were negatively associated with moderate severity and negative family history in keloids, moreover, HLA-DQB1*0201 (OR = 0.23, P(c) = 0.0003) and DQA1*0501 (OR = 0.43, P(c) = 0.0234) were less prevalent in patients with single site. CONCLUSION This study demonstrated the positive association of HLA-DQA1 and DQB1 alleles and haplotypes with keloids.

Five mutations of ATP2A2 gene in Chinese patients with Darier’s disease and a literature review of 86 cases reported in China

Darier’s disease (DD) is an autosomal dominantly inherited skin disorder characterized by loss of adhesion between epidermal cells (acantholysis) and abnormal keratinization. To date, at least 140 mutations in the ATP2A2 gene have been identified as the genetic basis of DD. Here we reported three familial and two sporadic Chinese DD patients totally with four missense mutations (N767D, M494I, M494L, C318F) and one splice-site mutation (1288–6A→G) in ATP2A2 gene, and presented a literature review of DD cases reported in China since 1989. Our data add new variants to the repertoire of ATP2A2 gene in DD and confirms that most mutations in the ATP2A2 gene are private and missense type. Likewise, the literature review indicates that DD is not uncommon in China and presents more information about genotype–phenotype correlations.

Exome sequencing identified a missense mutation of EPS8L3 in Marie Unna hereditary hypotrichosis

Background Marie Unna hereditary hypotrichosis (MUHH) is an autosomal dominant disorder characterised by coarse, wiry, twisted hair developed in early childhood and subsequent progressive hair loss. MUHH is a genetically heterogeneous disorder. No gene in 1p21.1–1q21.3 region responsible for MUHH has been identified. Methods Exome sequencing was performed on two affected subjects, who had normal vertex hair and modest alopecia, and one unaffected individual from a four-generation MUHH family of which our previous linkage study mapped the MUHH locus on chromosome 1p21.1–1q21.3. Results We identified a missense mutation in EPS8L3 (NM_024526.3: exon2: c.22G->A:p.Ala8Thr) within 1p21.1–1q21.3. Sanger sequencing confirmed the cosegregation of this mutation with the disease phenotype in the family by demonstrating the presence of the heterozygous mutation in all the eight affected and absence in all the seven unaffected individuals. This mutation was found to be absent in 676 unrelated healthy controls and 781 patients of other disease from another unpublished project of our group. Conclusions Taken together, our results suggest that EPS8L3 is a causative gene for MUHH, which was helpful for advancing us on understanding of the pathogenesis of MUHH. Our study also has further demonstrated the effectiveness of combining exome sequencing with linkage information for identifying Mendelian disease genes.

Two novel frame-shift mutations of ATP2A2 gene in Chinese patients with Darier's disease

Editor Darier’s disease (DD, Darier–White disease, keratosis follicularis; OMIM 124200) is a rare autosomal-dominant skin disorder characterized by warty papules and plaques with distribution over seborrhoeic areas (central trunk, flexures, scalp and forehead). 1 The pathogenic mutations have been identified in the ATP2A2 gene on chromosome 12q23-24.1. 2,3 To date, at least 150 ATP2A2 mutations have been reported in DD patients, and it seems that individual affected families have their own private mutations. Here we report two novel frame-shift mutations and a recurrent missense mutation in three Chinese patients with DD. Three sporadic cases (S-1, S-2, S-3) were collected from the Department of Dermatology, first affiliated hospital of Anhui Medical University, Hefei, China. Peripheral blood samples were collected from all available individuals and 100 unrelated population-matched controls. Genomic DNA was extracted from the peripheral blood using a kit (Promega, Madison, WI, UK) according to the manufacturer’s protocol. All 21 exons, including intron–exon boundaries, were amplified by polymerase chain reaction (PCR) using published primers. 4 After the amplification, products were examined on 1% agarose gels. The products were purified by QIA quick PCR Purification Kit (Qiagen, USA) and directly sequenced on CEQ8800 automated sequencer (Beckman Coulter, Inc, USA). Direct sequencing of the entire coding sequence of ATP2A2 gene in patients revealed two single nucleotid insertion mutations (1922insG, 2900insT) and a missense mutation (1031G → A; fig. 1). None of these mutations were found in 100 control individuals. One novel small insertion (1922insG) in S-1 that created shift in the reading frame is expected to result in a premature termination codon (PTC) four codons downstream. Another small insertion (2900insT) in exon 20 was found in S-2, which also resulted in PTC 13 codons downstream. The two mutations locate within the ATP-binding site and transmembrane