Identification of a Novel COL17A1 Compound Heterozygous Mutation in a Chinese Girl with Non-Herlitz Junctional Epidermolysis Bullosa

Summary:Non-Herlitz junctional epidermolysis bullosa(JEB-nH),an autosomal recessive bullous genodermatosis,is characterized by generalized skin blistering from birth onward,dental anomalies,universal alopecia and nail dystrophy.The underlying defect is mutation of the COLI7AI gene encoding the type XVⅡcollagen,resulting in losing structure for attachment of basal epithelial cells to the matrix.In present study,we described one case of congenitally affected female child aged 10 years,with skin blistering.Dermatologic examination revealed sparse,mild blisters on the face and hand,with profound enamel pitting of the teeth.Skin biopsy from proband's bullous skin displayed subepidermal bulla formation without acantholysis.The immunofluorescence of anti-type XVⅡcollagen antibody staining showed loss of type XVⅡcollagen staining at the basement membrane zone.A combination of whole exome sequencing(WES)and Sanger sequencing revealed the novel heterozygous mutations(C.4324C>T;p.Q1442^*and C.I 834G>C;p.G612R)in COLI7AI gene,which could be associated with the observed JEB-nH.One allele had a novel nonsense mutation(c.4324C>T;p.Q1442^*),resulting in nonsense-mediated mRNA decay and truncated collagen XVⅡ;the other allelc had a novel misscnse mutation of c.1834G>C;p.G612R in exon 22,causing a glycine-to-arginine substitution in the Gly-X-Y triple helical repeating motifs and decreasing the thermal stability of collagen XVⅡ.Our findings indicate that the genetic test based on WES can be useful in diagnosing JEB-nH patients.The novel pathogenic mutations identified would further expand our understanding of the mutation spectrum of COLI7AI gene in association with the inherited blistering diseases.

Alternative Oxidase Promotes Biofilm Formation of Candida albicans

This study was designed to analyze the effect of the mitochondrial respiratory pathways of Candida albicans （C. albicans） on the biofilm formation. The 2, 3-bis （2-methoxy- 4-nitro-5-sulfophenyl）-2H-tetrazolium-5-carboxanilide （XTT） reduction assay was used to measure the metabolic activities of biofilms formed by the C. albicans which were cultured in the presence of respiratory pathways inhibitors. The biofilms formed by the wide type （WT）, GOA1-deleted （GOA31）, GOAl-reconstituted （GOA32）, AOXla-deleted （AOX1） and AOX1b- deleted （AOX2） C. albicans strains were examined by the XTT reduction assay and fluorescence microscopy. The expression of adhesion-related genes BCR1, ALS1, ALS3, ECEI and HWP1 in the biofilms formed by the above five C. albicans strains was detected by real time polymerase chain reaction. It was found that the metabolic activity of biofilms formed by C. albicans was decreased in the presence of alternative oxidase inhibitor whereas it was increased in the presence of classical mitochondrial respiratory pathway complex Ⅲ or complex IV inhibitor. AOX1 strain produced scarce biofilms interspersed with few hyphal filaments. Moreover, no significant changes in the expression of BCR1 and ALS3 were observed in the AOX 1 strain, but the expression of ALS1 and ECE1 was down-regulated, and that of HWP1 was up-regulated. These results indicate that both AOX1 and AOX2 can promote the biofilm formation. However, AOX1a primarily plays a regulatory role in biofilm formation in the absence of inducers where the promoting effect is mainly achieved by promoting mycelial formation.