Zhirong Yao

Mutations in POFUT1, encoding protein O-fucosyltransferase 1, cause generalized Dowling-Degos disease.

Dowling-Degos disease (DDD), or reticular pigmented anomaly of the flexures, is a type of rare autosomal-dominant genodermatosis characterized by reticular hyperpigmentation and hypopigmentation of the flexures, such as the neck, axilla, and areas below the breasts and groin, and shows considerable heterogeneity. Loss-of-function mutations of keratin 5 (KRT5) have been identified in DDD individuals. In this study, we collected DNA samples from a large Chinese family affected by generalized DDD and found no mutation of KRT5. We performed a genome-wide linkage analysis of this family and mapped generalized DDD to a region between rs1293713 and rs244123 on chromosome 20 [corrected]. By exome sequencing, we identified nonsense mutation c.430G>T (p.Glu144(∗)) in POFUT1, which encodes protein O-fucosyltransferase 1, in the family. Study of an additional generalized DDD individual revealed the heterozygous deletion mutation c.482delA (p.Lys161Serfs(∗)42) in POFUT1. Knockdown of POFUT1 reduces the expression of NOTCH1, NOTCH2, HES1, and KRT5 in HaCaT cells. Using zebrafish, we showed that pofut1 is expressed in the skin and other organs. Morpholino knockdown of pofut1 in zebrafish produced a phenotype characteristic of hypopigmentation at 48 hr postfertilization (hpf) and abnormal melanin distribution at 72 hpf, replicating the clinical phenotype observed in our DDD individuals. At 48 and 72 hpf, tyrosinase activities decreased by 33% and 45%, respectively, and melanin protein contents decreased by 20% and 25%, respectively. Our findings demonstrate that POFUT1 mutations cause generalized DDD. These results strongly suggest that the protein product of POFUT1 plays a significant and conserved role in melanin synthesis and transport.

Mutations in the filaggrin gene in Han Chinese patients with atopic dermatitis

To cite this article: Zhang H, Guo Y, Wang W, Shi M, Chen X, Yao Z. Mutations in the filaggrin gene in Han Chinese patients with atopic dermatitis. Allergy 2011; 66: 420–427.

Mutational spectrum of the ADAR1 gene in dyschromatosis symmetrica hereditaria

Dyschromatosis symmetrica hereditaria (DSH) is a rare autosomal dominant cutaneous disorder characterized by a mixture of hyperpigmented and hypopigmented macules of various sizes on the extremities and caused by the mutations of adenosine deaminase acting on RNA1 (ADAR1) gene. We screened 14 unrelated families or sporadic cases for mutation in the full coding sequence of this gene. Eight novel heterozygous mutations of ADAR1 and four known mutations were identified, including four missense mutations (p.R26K, p.Y1192D, p.R916Q, p.R1155W), six frameshift mutations (p.N205fsX217, p.V211fsX217, p.V404fsX417, p.I914fsX927, p.L1053fsX1076, p.L1070fs1092), and two nonsense mutations (p.R474X, p.R1096X). Interestingly, we failed to detect any mutations of ADAR1 in one family. Including our data, there are now 93 different mutations reported in 105 independent patients that we have tabulated. From the review of clinical features in these reports, we found that the same mutation could lead to different phenotypes even in the same family and did not establish a clear correlation between genotypes and phenotypes. Finally this study is useful for functional studies of the protein and to define a diagnostic strategy for mutation screening of the ADAR1 gene.

Prevalence and Distribution Profiles of Candida parapsilosis, Candida orthopsilosis and Candida metapsilosis Responsible for Superficial Candidiasis in a Chinese University Hospital

The Candida parapsilosis complex consists of C. parapsilosis sensu stricto, C. orthopsilosis and C. metapsilosis. Recently, many studies described the prevalence of this species complex mainly in invasive candidiasis. Additionally, data showed that these three species are different in virulence and in vitro drug susceptibility. However, to our knowledge, the prevalence and distribution of the species complex in superficial candidiasis is not very clear to date. In this study, 2,128 Candida isolates from specimens of superficial candidiasis were collected over a 1-year period. Combination of routine and molecular tools, a total of 214 samples were identified to be positive for the C. parapsilosis complex (10.1%), of which 198 (92.5%) were monofungal and 16 (7.5%) were polyfungal. Among the 198 monofungal isolates, 191 (96.5%) were identified as C. parapsilosis sensu stricto, 5 (2.5%) as C. metapsilosis, and 2 (1.0%) as C. orthopsilosis species based on the molecular method. All C. parapsilosis complex isolates from the 16 polyfungal populations were found to be C. parapsilosis sensu stricto. Further analysis showed that the distribution profiles of the C. parapsilosis complex in adult patients were different from that in pediatric patients, and the prevalence rate of it varied greatly by sites of isolation. This study provides insight into the epidemiology of the species complex in superficial candidiasis.

Mutations analysis in filaggrin gene in northern China patients with atopic dermatitis

Background  Recently, we have reported filaggrin mutations (FLG) of atopic dermatitis in southern China. However, there have been few detailed reports of FLG mutations of patients with AD in northern China by now.

Development of a Singleplex PCR Assay for Rapid Identification and Differentiation of Cryptococcus neoformans var. grubii, Cryptococcus neoformans var. neoformans, Cryptococcus gattii, and Hybrids

ABSTRACT A singleplex PCR assay using a single primer pair targeting the putative sugar transporter gene was developed here to distinguish Cryptococcus neoformans var. grubii, Cryptococcus neoformans var. neoformans, and Cryptococcus gattii according to the distinct size of the amplicon. The interspecies and intravarietal hybrids were also characterized on the basis of distinct combined profiles of amplicons. This PCR assay is a rapid, simple, and reliable approach suitable for laboratory diagnoses and large-scale epidemiologic studies.

A novel recombinant lineage’s contribution to the outbreak of coxsackievirus A6-associated hand, foot and mouth disease in Shanghai, China, 2012-2013

Since late 2012, coxsackievirus A6 (CVA6) has gradually become the predominant pathogen responsible for hand-foot-mouth disease (HFMD) in several provinces of China. A total of 626 patients diagnosed with HFMD in Shanghai, China from January 2012 to September 2013 were enrolled in this study. Of these, 292 CVA6 infected cases were subjected to clinical analyses. Whole-genome sequencing, recombination and phylogenetic analyses were also performed. A recombinant CVA6 monophyletic lineage was found during an outbreak of CVA6-associated HFMDs in Shanghai, China in November 2012, and accounted for 21.9% (64/292) of the CVA6 strains during the study period. Recombination analyses showed that the 2C gene of the novel CVA6 virus was probably derived from a coxsackievirus A4 (CVA4) strain circulating in the population. Clinical observation showed that this recombinant CVA6 virus led to a more generalized rash than did the non-recombinant CVA6 virus. This newly emerged CVA6 lineage was associated with a considerable proportion of HFMD cases from 2012 to 2013 in Shanghai, and poses a potential threat to public health.

Molecular Characterization of NF1 and Neurofibromatosis Type 1 Genotype-Phenotype Correlations in a Chinese Population

Neurofibromatosis type 1 (NF1) is an autosomal dominant hereditary disease that is primarily characterized by multiple café au-lait spots (CALs) and skin neurofibromas, which are attributed to defects in the tumor suppressor NF1. Because of the age-dependent presentation of NF1, it is often difficult to make an early clinical diagnosis. Moreover, identifying genetic alterations in NF1 patients represents a complex challenge. Currently, there are no effective detective methods, and no comprehensive NF1 mutation data are available for mainland China. We screened 109 Chinese patients from 100 families with NF1-like phenotypes (e.g., CALs, neurofibromas, etc.) using Sanger sequencing, multiplex ligation-dependent probe amplification and cDNA sequencing. NF1 mutations were identified in 97 individuals, among which 34 intragenic mutations have not previously been reported. Our exhaustive mutational analysis detected mutations in 89% (89/100) of the NF1-like probands and 93% (70/75) of subjects fulfilling the National Institutes of Health (NIH) criteria. Our findings indicate that individuals who exclusively present with multiple CALs exhibit a high possibility (76%) of having NF1 and show a significantly lower mutation rate (p = 0.042) compared with subjects who fulfill the NIH criteria, providing clinicians with the information that subjects only with multiple CALs harbor a considerable possibility (24%) of being attributed to other comparable diseases.

Analyses of FLG mutation frequency and filaggrin expression in isolated ichthyosis vulgaris (IV) and atopic dermatitis-associated IV.

Background  Ichthyosis vulgaris (IV; OMIM 146700) is a very common inherited skin disorder. Loss‐of‐function mutations in the filaggrin gene (FLG) have been identified as the cause of IV. In a previous study, we found that the percentage of FLG null mutations was lower in IV associated with atopic dermatitis (AD) than in IV not associated with AD (isolated IV). We speculated that some clinical manifestations of IV in patients with AD are not induced by FLG mutations.

Filaggrin gene mutations are associated with independent atopic asthma in Chinese patients

Asthma is a complex disease manifesting as two major phenotypes, namely nonatopic and atopic asthma (AA). AA is the most common form, particularly in preschool children. On the basis of two meta-analyses, it was concluded that no association exists between FLG mutations and asthma without the coexistence of atopic dermatitis (AD) (1, 2). However, Ponińska et al. (3) reported that filaggrin gene (FLG) defects were significantly associated with AA without the coexistence of AD in a Polish population. Through a previous study conducted by our group, we recently confirmed that FLG defects are significantly associated with asthma combined with AD in Chinese patients (4). Nevertheless, the extent to which this association is present in AD-free AA patients in China is unclear. In the current study, 121 AA patients without AD were examined using an overlapping PCR strategy. This study was approved by the Ethics Committees of the Shanghai Jiaotong University School of Medicine. Written informed consents were given by all the participants before enrollment in the study. The clinical diagnosis of AA was made by two experienced physicians and one experienced dermatologist. The diagnosis of AA in all the patients was conducted in accordance with the International Global Initiative for Asthma guidelines. To exclude that these children had AD earlier in life, AD status was determined by physical examination, gathering information through medical record, and interviewing the parents of the patients (with questions such as ‘Did the child have atopic dermatitis?’). To compare the frequency of FLG mutations, DNA samples from 301 normal healthy, unrelated Chinese individuals were also included. PCR primers and conditions were described previously by Sandilands et al. (5). The median age of the patients with AA was 5.0 ± 3.8 years. The majority of the patients (95.5%) had elevated ECP levels (>8.0 lg/l) and/or elevated IgE levels (>100.0 ll/ml). The median of the IgE level in boys was significantly higher than that in girls (178 ± 440.1 vs 53.9 ± 116.8, P = 0.001), and the level of ECP in boys showed no significant difference from that in girls. The average age of the 301 controls (111 girls and 190 boys) was 16.49 ± 1.75 years. In this study, two novel mutations (S1302X and Q2397X) and two recurrent mutations (3321delA and K4671X) were identified in patients with AA. The data on FLG mutations are summarized in Table 1. Three FLG mutations (3222del4, 3321delA, and K4671X) were found in 12 healthy controls. A total of 19 (15.7%) patients with AA were identified as having at least one FLG mutation (combined minor allele frequency: 8.3, n = 242). The associations between AA and the two most common mutations were statistically significant (3321delA: OR = 5.8, 95% CI: 1.5– 22.1, P = 0.010; K4671X: OR = 3.1, 95% CI: 1.3–7.7, P = 0.010). The rarer FLG variants, S1302X and Q2397X, were nonsignificantly associated with AA. However, the combined null genotype showed a highly significant association (OR = 3.9, 95% CI: 2.0–7.9, P = 3.02 · 10). Mutations 3321delA and K4671X were the two most common mutations in the AA cohorts. 3321delA was also the most common mutation in Japanese, Singaporean Chinese and Taiwanese patients. Mutation K4671X, however, was not the common mutation in these populations (6). In a recent study, Chen et al. (6) screened 92 Singaporean-Chinese individuals with IV and/or AD, and K4671X was not found in this cohort. Perhaps K4671X is a common mutation specific to the Chinese mainland population. The results of this study clearly confirmed a significant association of the combined or separate genotype of 3321delA and K4671X mutation in patients with AA but without AD. The discrepancy among these findings probably reflects different genetic and environmental backgrounds in various populations. In China, FLG null mutations are strongly associated with AD-free atopic asthma.