Xiaoxiao Yan

Genomewide association study of leprosy.

BACKGROUND The narrow host range of Mycobacterium leprae and the fact that it is refractory to growth in culture has limited research on and the biologic understanding of leprosy. Host genetic factors are thought to influence susceptibility to infection as well as disease progression. METHODS We performed a two-stage genomewide association study by genotyping 706 patients and 1225 controls using the Human610-Quad BeadChip (Illumina). We then tested three independent replication sets for an association between the presence of leprosy and 93 single-nucleotide polymorphisms (SNPs) that were most strongly associated with the disease in the genomewide association study. Together, these replication sets comprised 3254 patients and 5955 controls. We also carried out tests of heterogeneity of the associations (or lack thereof) between these 93 SNPs and disease, stratified according to clinical subtype (multibacillary vs. paucibacillary). RESULTS We observed a significant association (P<1.00x10(-10)) between SNPs in the genes CCDC122, C13orf31, NOD2, TNFSF15, HLA-DR, and RIPK2 and a trend toward an association (P=5.10x10(-5)) with a SNP in LRRK2. The associations between the SNPs in C13orf31, LRRK2, NOD2, and RIPK2 and multibacillary leprosy were stronger than the associations between these SNPs and paucibacillary leprosy. CONCLUSIONS Variants of genes in the NOD2-mediated signaling pathway (which regulates the innate immune response) are associated with susceptibility to infection with M. leprae.

Genome-wide linkage, exome sequencing and functional analyses identify ABCB6 as the pathogenic gene of dyschromatosis universalis hereditaria

Background As a genetic disorder of abnormal pigmentation, the molecular basis of dyschromatosis universalis hereditaria (DUH) had remained unclear until recently when ABCB6 was reported as a causative gene of DUH. Methodology We performed genome-wide linkage scan using Illumina Human 660W-Quad BeadChip and exome sequencing analyses using Agilent SureSelect Human All Exon Kits in a multiplex Chinese DUH family to identify the pathogenic mutations and verified the candidate mutations using Sanger sequencing. Quantitative RT-PCR and Immunohistochemistry was performed to verify the expression of the pathogenic gene, Zebrafish was also used to confirm the functional role of ABCB6 in melanocytes and pigmentation. Results Genome-wide linkage (assuming autosomal dominant inheritance mode) and exome sequencing analyses identified ABCB6 as the disease candidate gene by discovering a coding mutation (c.1358C>T; p.Ala453Val) that co-segregates with the disease phenotype. Further mutation analysis of ABCB6 in four other DUH families and two sporadic cases by Sanger sequencing confirmed the mutation (c.1358C>T; p.Ala453Val) and discovered a second, co-segregating coding mutation (c.964A>C; p.Ser322Lys) in one of the four families. Both mutations were heterozygous in DUH patients and not present in the 1000 Genome Project and dbSNP database as well as 1,516 unrelated Chinese healthy controls. Expression analysis in human skin and mutagenesis interrogation in zebrafish confirmed the functional role of ABCB6 in melanocytes and pigmentation. Given the involvement of ABCB6 mutations in coloboma, we performed ophthalmological examination of the DUH carriers of ABCB6 mutations and found ocular abnormalities in them. Conclusion Our study has advanced our understanding of DUH pathogenesis and revealed the shared pathological mechanism between pigmentary DUH and ocular coloboma.

Evidence for an association of HLA-DRB1*15 and DRB1*09 with leprosy and the impact of DRB1*09 on disease onset in a Chinese Han population.

BackgroundHuman leukocyte antigens (HLAs) have been proposed to modulate the immune response to Mycobacterium leprae. The association of HLA-DRB1 with leprosy has been reported in several populations, but not in a Chinese population.MethodsThe polymerase chain reaction-sequence-specific oligonucleotide probe with Luminex100 (PCR-SSOP-Luminex) method was used to genotype HLA-DRB1 alleles in 305 leprosy patients and 527 healthy control individuals.ResultsThe HLA-DRB1*15 allele was significantly more prevalent among leprosy patients than healthy controls, whereas the frequency of the HLA-DRB1*09 allele was lower among leprosy patients, especially those with early-onset disease.ConclusionHLA-DRB1 alleles are associated with leprosy susceptibility in a Chinese population. The HLA-DRB1*09 allele was found to be protective exclusively in a subset of early-onset leprosy patients.

CARD9 mutation linked to Corynespora cassiicola infection in a Chinese patient.

Corynespora cassiicola is a plant pathogen associated with leaf‐spotting disease. The fungus has been found on diverse substrates: leaves, stems and roots of plants; nematode cysts and human skin. It rarely causes human infections. Here we report one case of subcutaneous phaeohyphomycosis caused by C. cassiicola with prominent tissue necrosis in a woman. All of her clinical features pointed towards a genetic linkage. Hence, whole‐exome sequencing and Sanger sequencing were performed on this patient. One mutation of CARD9 was detected.

Eight Novel Mutations of ATP2C1 Identified in 17 Chinese Families with Hailey-Hailey Disease

Background: Hailey-Hailey disease (HHD) is a rare autosomal dominantly inherited dermatosis, characterized by persistent blisters and erosions of the skin. It was recently discovered that HHD was caused by mutations in the ATP2C1 gene, a Ca2+ pump located in the Golgi apparatus. Observation: In this study, we sequenced the ATP2C1 gene from blood samples of 31 patients in 17 unrelated Chinese families and 120 healthy individuals. Eight novel mutations were identified in 9families, including 3 insertion/deletions (nt 1464–1487/1462–1485 del, 1523 del AT, 2375 del TTGT), 3 splicing-site mutations [360(–2)a→g, 1415(–2)a→c, 2243(+2)t→c], and 2 missense mutations (P307L, D648Y). Conclusion: Eight mutations were found in 8 unrelated families and 1 sporadic case, and these new findings have further improved our understanding of the role of ATP2C1 in HHD.

Chromosome 2p14 is linked to susceptibility to leprosy.

Background A genetic component to the etiology of leprosy is well recognized but the mechanism of inheritance and the genes involved are yet to be fully established. Methodology A genome-wide single nucleotide polymorphism (SNP) based linkage analysis was carried out using 23 pedigrees, each with 3 to 7 family members affected by leprosy. Multipoint parametric and non-parametric linkage analyses were performed using MERLIN 1.1.1. Principal Findings Genome-wide significant evidence for linkage was identified on chromosome 2p14 with a heterogeneity logarithm of odds (HLOD) score of 3.51 (rs1106577) under a recessive model of inheritance, while suggestive evidence was identified on chr.4q22 (HLOD 2.92, rs1349350, dominant model), chr. 8q24 (HLOD 2.74, rs1618523, recessive model) and chr.16q24 (HLOD 1.93, rs276990 dominant model). Our study also provided moderate evidence for a linkage locus on chromosome 6q24–26 by non-parametric linkage analysis (rs6570858, LOD 1.54, p = 0.004), overlapping a previously reported linkage region on chromosome 6q25–26. Conclusion A genome-wide linkage analysis has identified a new linkage locus on chromosome 2p14 for leprosy in Pedigrees from China.

Six novel ATP2C1 mutations identified in Chinese patients with Hailey–Hailey disease

Jiali Han Clinical Research Program, Department of Dermatology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, United States Channing Laboratory of the Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, United States Program in Molecular and Genetic Epidemiology, Department of Epidemiology, Harvard School of Public Health, Boston, MA, United States

Reliability and validity of the Chinese version of the autoimmune bullous disease quality of life (ABQOL) questionnaire

BackgroundThe autoimmune bullous diseases quality of life (ABQOL) questionnaire was recently developed by an Australian group and has been validated in Australian and North American patient cohorts. It is a 17-item, multidimensional, self-administered English questionnaire. The study aimed to validate the Chinese version of the ABQOL questionnaire and evaluate the reliability in Chinese patients.MethodsThe Chinese version of the ABQOL questionnaire was produced by forward-backward translation and cross-cultural adaptation of the original English version. The ABQOL questionnaire was then distributed to a total of 101 patients with autoimmune bullous diseases (AIBDs) together with the Dermatology Life Quality Index (DLQI) and the 36-item Short Form Health Survey (SF-36). Validity was analyzed across a range of indices and reliability was assessed using internal consistency and test-retest methods.ResultsThe Chinese version of the ABQOL questionnaire has a high internal consistency (Cronbach’s alpha coefficient, 0.88) and test-retest reliability (the intraclass correlation coefficient, 0.87). Face and content validity were satisfactory. Convergent validity testing showed that the correlation coefficients for the ABQOL and DLQI was 0.77 and for the ABQOL and SF-36 was −0.62. In terms of discriminant validity, there was no significant difference between the proportions of insensitive items in ABQOL and DLQI (p = 0.236). There was no significant difference between the proportions of insensitive items in ABQOL and SF-36 (p = 0.823).ConclusionsThe Chinese version of the ABQOL questionnaire has adequate validity and reliability. It may constitute a useful instrument to measure disease burden in Chinese patients with AIBDs.

A case of pemphigoid gestationis with concurrent IgG antibodies to BP180, BP230 and type VII collagen.

A 22‐year‐old primigravida had a pruritic, erythematous, bullous eruption on the skin during the 26th week of gestation. After delivery the eruption flared up. The diagnosis of pemphigoid gestationis was confirmed based on histopathological and immunofluorescence findings. The result of immunoblotting showed IgG autoantibodies which reacted against BP230 in epidermal extracts and 290 kDa type VII collagen in dermal extracts. The BP180 antibodies were also detected by an enzyme‐linked immunosorbent assay BP180NC16a diagnosis kit. Pulsed corticosteroid and cyclophosphamide resulted in a favourable response at the acute stage. The patient was cured in 2 years. The analysis of the patients autoantibodies provides strong evidence for the involvement of epitope spreading in her autoimmune disease.

Chinese version of the Treatment of Autoimmune Bullous Disease Quality of Life questionnaire: Reliability and validity.

Background: Treatments for autoimmune blistering disease carry significant risks of medical complications and can affect the patients quality of life. Recently, the Treatment of Autoimmune Bullous Disease Quality of Life questionnaire was developed in Australia. Objective: The objective of this study was to evaluate the reliability and validity of the Chinese version of the Treatment of Autoimmune Bullous Disease Quality of Life questionnaire in Chinese patients with autoimmune blistering diseases. Methods: The Chinese version of the Treatment of Autoimmune Bullous Disease Quality of Life questionnaire was produced by forward-backward translation and cross-cultural adaptation of the original English version. Autoimmune blistering disease patients recruited in the study self-administered the Chinese Treatment of Autoimmune Bullous Disease Quality of Life questionnaire, the Dermatology Life Quality Index and the 36-item Short-Form Health Survey. Reliability of the Chinese Treatment of Autoimmune Bullous Disease Quality of Life was evaluated using internal consistency and test-retest (days 0 and 7) methods. Validity was analyzed by face, content, construct, convergent and discriminant validity measures. Results: A total of 86 autoimmune blistering disease patients were recruited for the study. Cronbachs alpha coefficient was 0.883 and the intraclass correlation coefficient was 0.871. Face and content validities were satisfactory. Convergent validity testing revealed correlation coefficients of 0.664 for the Treatment of Autoimmune Bullous Disease Quality of Life and Dermatology Life Quality Index and –0.577 for the Treatment of Autoimmune Bullous Disease Quality of Life and 36-item Short-Form Health Survey. With respect to discriminant validity, no significant differences were observed in the Treatment of Autoimmune Bullous Disease Quality of Life scores of men and women (t = 0.251, P = 0.802), inpatients and outpatients (t = 0.447, P = 0.656), patients on steroids and steroid-sparing medications (t = 0.672, P = 0.503) and patients with different autoimmune blistering disease subtypes (F = 0.030, P = 0.971). Limitations: Illiterate patients were excluded from the study. The patients were from a single hospital and most of their conditions were in a relatively stable status. Conclusion: The Chinese version of the Treatment of Autoimmune Bullous Disease Quality of Life questionnaire is a reliable and valid instrument to measure treatment burden and to serve as an end point in clinical trials in Chinese autoimmune blistering disease patients.