Jianzhong Zhang

Psoriasis genome-wide association study identifies susceptibility variants within LCE gene cluster at 1q21.

We report the first large genome-wide association study (GWAS) in a Chinese population to identify susceptibility variants for psoriasis using a two-stage case-control design. In the first stage, we carried out a genome-wide association analysis in 1,139 cases and 1,132 controls of Chinese Han ancestry using Illumina Human 610-Quad BeadChips. In the second stage, we took top SNPs forward for replication in two independent samples of 5,182 cases and 6,516 controls of Chinese Han ancestry, and 539 cases and 824 controls of Chinese Uygur ancestry. In addition to the strong replication for two known susceptibility loci MHC (rs1265181, P = 1.93 × 10−208, OR = 22.62) and IL12B (rs3213094, Pcombined = 2.58 × 10−26, OR = 0.78), we identified a new susceptibility locus within the LCE gene cluster on 1q21 (rs4085613, Pcombined = 6.69 × 10−30, OR = 0.76).

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.

Genome-wide association study for vitiligo identifies susceptibility loci at 6q27 and the MHC

We conducted a genome-wide association study of generalized vitiligo in the Chinese Han population by genotyping 1,117 cases and 1,429 controls. The 34 most promising SNPs were carried forward for replication in samples from individuals of the Chinese Han (5,910 cases and 9,916 controls) and Chinese Uygur (713 cases and 824 controls) populations. We identified two independent association signals within the major histocompatibility complex (MHC) region (rs11966200, Pcombined = 1.48 × 10−48, OR = 1.90; rs9468925, Pcombined = 2.21 × 10−33, OR = 0.74). Further analyses suggested that the strong association at rs11966200 might reflect the reported association of the HLA-A*3001, HLA-B*1302, HLA-C*0602 and HLA-DRB1*0701 alleles and that the association at rs9468925 might represent a previously unknown HLA susceptibility allele. We also identified one previously undescribed risk locus at 6q27 (rs2236313, Pcombined = 9.72 × 10−17, OR = 1.20), which contains three genes: RNASET2, FGFR1OP and CCR6. Our study provides new insights into the genetic basis of vitiligo.

A large-scale screen for coding variants predisposing to psoriasis.

To explore the contribution of functional coding variants to psoriasis, we analyzed nonsynonymous single-nucleotide variants (SNVs) across the genome by exome sequencing in 781 psoriasis cases and 676 controls and through follow-up validation in 1,326 candidate genes by targeted sequencing in 9,946 psoriasis cases and 9,906 controls from the Chinese population. We discovered two independent missense SNVs in IL23R and GJB2 of low frequency and five common missense SNVs in LCE3D, ERAP1, CARD14 and ZNF816A associated with psoriasis at genome-wide significance. Rare missense SNVs in FUT2 and TARBP1 were also observed with suggestive evidence of association. Single-variant and gene-based association analyses of nonsynonymous SNVs did not identify newly associated genes for psoriasis in the regions subjected to targeted resequencing. This suggests that coding variants in the 1,326 targeted genes contribute only a limited fraction of the overall genetic risk for psoriasis.

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.

Whole-exome SNP array identifies 15 new susceptibility loci for psoriasis

Genome-wide association studies (GWASs) have reproducibly associated ∼40 susceptibility loci with psoriasis. However, the missing heritability is evident and the contributions of coding variants have not yet been systematically evaluated. Here, we present a large-scale whole-exome array analysis for psoriasis consisting of 42,760 individuals. We discover 16 SNPs within 15 new genes/loci associated with psoriasis, including C1orf141, ZNF683, TMC6, AIM2, IL1RL1, CASR, SON, ZFYVE16, MTHFR, CCDC129, ZNF143, AP5B1, SYNE2, IFNGR2 and 3q26.2-q27 (P<5.00 × 10−08). In addition, we also replicate four known susceptibility loci TNIP1, NFKBIA, IL12B and LCE3D–LCE3E. These susceptibility variants identified in the current study collectively account for 1.9% of the psoriasis heritability. The variant within AIM2 is predicted to impact protein structure. Our findings increase the number of genetic risk factors for psoriasis and highlight new and plausible biological pathways in psoriasis.

Association Analyses Identify Three Susceptibility Loci for Vitiligo in the Chinese Han Population

To identify susceptibility loci for vitiligo, we extended our previous vitiligo genome-wide association study with a two-staged replication study that included 6,857 cases and 12,025 controls from the Chinese Han population. We identified three susceptibility loci, 12q13.2 (rs10876864, P(combined)=8.07 × 10(-12), odds ratio (OR)=1.18), 11q23.3 (rs638893, P(combined)=2.47 × 10(-9), OR=1.22), and 10q22.1 (rs1417210, P(combined)=1.83 × 10(-8), OR=0.88), and confirmed three previously reported loci for vitiligo, 3q28 (rs9851967, P(combined)=8.57 × 10(-8), OR=0.88), 10p15.1 (rs3134883, P(combined)=1.01 × 10(-5), OR=1.11), and 22q12.3 (rs2051582, P(combined)=2.12 × 10(-5), OR=1.14), in the Chinese Han population. The most significant single-nucleotide polymorphism in the 12q13.2 locus is located immediately upstream of the promoter region of PMEL, which encodes a major melanocyte antigen and has expression loss in the vitiligo lesional skin. In addition, both 12q13.2 and 11q23.3 loci identified in this study are also associated with other autoimmune diseases such as type 1 diabetes and systemic lupus erythematosus. These findings provide indirect support that vitiligo pathogenesis involves a complex interplay between immune regulatory factors and melanocyte-specific factors. They also highlight similarities and differences in the genetic basis of vitiligo in Chinese and Caucasian populations.

A novel 3017‐bp deletion mutation in the FERMT1 (KIND1) gene in a Chinese family with Kindler syndrome

SIR, Kindler syndrome (KS; OMIM 173650) is a rare autosomal recessive genodermatosis characterized by congenital acral blister formation and a variable degree of photosensitivity, which resolve slowly with age, followed by generalized progressive poikiloderma with extensive cutaneous atrophy. Gingival fragility, progressive periodontitis and gastrointestinal involvement occur in some patients. The KS causative gene, FERMT1 (formerly KIND1), encodes a 677-amino acid protein, kindlin-1, which is implicated in the organization and anchorage of the actin cytoskeleton to integrin-associated platforms. It was reported that loss of kindlin-1 in keratinocytes leads to loss of cell polarity, decreased adhesion, reduced cell proliferation and increased apoptosis. Thus far, 33 different FERMT1 (KIND1) mutations have been identified in more than 100 cases of KS. Most of the reported mutations are point mutations, small insertions or deletions, which could be identified by routinely used strategies based on polymerase chain reaction (PCR) amplification of each coding exon and flanking intronic regions, followed by direct sequencing. In the present study, we identified a novel homozygous 3017-bp deletion mutation spanning exons 7–9 in the FERMT1 gene in a Chinese family with KS. The patient was a 23-year-old Chinese man born of consanguineous parents. During the neonatal period, he developed acral blisters, which appeared spontaneously or after trauma. From the age of 2 years, he developed facial and acral erythema following sun exposure. The blistering and photosensitivity improved with age and were followed by progressive poikiloderma. Subsequently, he developed gingival fragility with bleeding and recurrent angular cheilitis, which restricted mouth opening. He had a circumcision when he was 5 years old. Physical examination showed short stature (height 158 cm, weight 49 kg). Mottled hyperand hypo-pigmentation and telangiectasia were revealed over the face, neck and upper parts of the chest (Fig. 1a). Skin atrophy was seen on the trunk and extremities, with ‘cigarette paper’-like wrinkling on the dorsa of the hands and feet (Fig. 1b). Diffuse hyperkeratosis of the palms and soles, webbing and severe contracture of the fingers, nail dystrophy, gingival swelling, ectropion of the lower lids and alopecia areata were also observed (Fig. 1c–e). Skin biopsies were obtained from involved areas. Histopathological examinations showed hyperkeratosis, atrophy of the epidermis, vacuolization of the basal layer, melanophages in the papillary dermis and dilation of blood vessels (Fig. 1f). Electron microscopy showed reduplication of the lamina densa (Fig. 1g). Blood samples were obtained from the patient and available family members following written informed consent. DNA was extracted from peripheral blood lymphocytes. Exons 1–6 and exons 10–15 of FERMT1 were successfully amplified in the patient with primers designed by the primer design program DNAMAN 4.0 (Lynnon Biosoft Inc., Vandreuil, QC, Canada). No mutation was identified by sequencing these exons and their flanking intronic regions. However, a DNA sample from the patient failed to yield PCR amplification products for exons 7, 8 and 9, while they could be amplified in normal controls. Therefore, we presumed the possibility of the presence of a homozygous large deletion mutation spanning exons 7–9 in the patient’s genomic DNA. To sublocalize the deletion breakpoints, a multiple PCR amplification of nonoverlapping fragments was performed with primer pairs positioned in the middle of intron 6 (n6F and n6R) and in the middle of intron 9 (n9F and n9R). The results of these PCR amplifications enabled us to circumscribe the deleted interval. Subsequently, the junction fragment was PCR-amplified with template DNA from the patient using a pair of primers, br1F in intron 6 (forward) and br1R in intron 9 (reverse), which were designed as close as possible to the deletion breakpoints. A fragment of ~0Æ8 kb of product, instead of ~3Æ8 kb of wild-type PCR product, was obtained from the patient. Sequencing of the 0Æ8-kb fragment revealed the 5¢ and 3¢ breakpoints and a large deletion mutation of 3017 bp in FERMT1 (g.63601_66617del, GenBank AL118505, reverse complemented strand) (Fig. 2a,b). To verify this large deletion mutation in the healthy carriers and normal controls, two PCR reactions were performed. In the first reaction, a pair of primers, br2F (forward) and br2R (reverse) that were close to the breakpoints, were used to amplify a 297-bp fragment in the mutated allele. The second reaction was performed to amplify exon 8, and yielded a 568-bp product in the normal allele. As shown in Figure 2c, the reactions yielded a single band of 297 bp in the patient, two bands of 297 and 568 bp in healthy carriers and a band of 568 bp in the normal controls. Using this assay, the deletion mutation was not detected in any allele of 50 healthy controls. The breakpoint sequence was compared with 100 bp of wild-type sequence on each side. A short homology sequence

Clinical Features of Adult/Adolescent Atopic Dermatitis and Chinese Criteria for Atopic Dermatitis

Background:Atopic dermatitis (AD) is an inflammatory skin disease characterized by chronic recurrent dermatitis with profound itching. Most patients have personal and/or family history of atopic diseases. Several criteria have been proposed for the diagnosis of AD. Although the clinical features of childhood AD have been widely studied, there has been less large-scale study on adult/adolescent AD. The aim of this study was to investigate the clinical features of adult/adolescent patients with chronic symmetrical eczema/AD and to propose Chinese diagnostic criteria for adult/adolescent AD. Methods:A hospital-based study was performed. Forty-two dermatological centers participated in this study. Adult and adolescent patients (12 years and over) with chronic symmetrical eczema or AD were included in this study. Questionnaires were completed by both patients and investigators. The valid questionnaires were analyzed using EpiData 3.1 and SPSS 17.0 software. Results:A total of 2662 valid questionnaires were collected (1369 male and 1293 female). Of all 2662 patients, 2062 (77.5%) patients had the disease after 12 years old, while only 600 (22.5%) patients had the disease before 12 years old, suggesting late-onset eczema/AD is common. Two thousand one hundred and thirty-nine (80.4%) patients had the disease for more than 6 months. One thousand one hundred and forty-four (43.0%) patients had a personal and/or family history of atopic diseases. One thousand five hundred and forty-eight (58.2%) patients had an elevated total serum IgE and/or eosinophilia and/or positive allergen-specific IgE. Based on these clinical and laboratory features, we proposed Chinese criteria for adult/adolescent AD. Of all 2662 patients, 60.3% were satisfied with our criteria, while only 48.2% satisfied with Hanifin Rajka criteria and 32.7% satisfied with Williams criteria, suggesting a good sensitivity of our criteria in adult/adolescent AD patients. Conclusion:Late-onset of eczema or AD is common. The clinical manifestations of AD are heterogeneous. We have proposed Chinese diagnostic criteria for adolescent and adult AD, which are simple and sensitive for diagnosis of adult/adolescent AD.

Novel Mutations in PSENEN Gene in Two Chinese Acne Inversa Families Manifested as Familial Multiple Comedones and Dowling-Degos Disease

Background:Acne inversa (AI), also called hidradenitis suppurativa, is a chronic, inflammatory, recurrent skin disease of the hair follicle. Familial AI shows autosomal-dominant inheritance caused by mutations in the &ggr;-secretase genes. This study was aimed to identify the specific mutations in the &ggr;-secretase genes in two Chinese families with AI. Methods:In this study, two Chinese families with AI were investigated. All the affected individuals in the two families mainly manifested with multiple comedones, pitted scars, and a few inflammatory nodules on their face, neck, trunk, axilla, buttocks, upper arms, and thighs. Reticulate pigmentation in the flexures areas resembled Dowling-Degos disease clinically and pathologically. In addition, one of the affected individuals developed anal canal squamous cell carcinoma. Molecular mutation analysis of &ggr;-secretase genes including PSENEN, PSEN1, and NCSTN was performed by polymerase chain reaction and direct DNA sequencing. Results:Two novel mutations of PSENEN gene were identified, including a heterozygous missense mutation c.194T>G (p.L65R) and a splice site mutation c.167-2A>G. Conclusions:The identification of the two mutations could expand the spectrum of mutations in the &ggr;-secretase genes underlying AI and provide valuable information for further study of genotype-phenotype correlations.