Search

Background: Genome-wide association studies (GWASs) have revealed a large number of genetic risk loci for many autoimmune diseases. One clear finding emerging from the published genetic studies of autoimmunity is that different autoimmune diseases, such as psoriasis and systemic lupus erythematosus (SLE), share susceptibility loci. Our study explores additional susceptibility loci shared by psoriasis and SLE in the Chinese Han population., Methods: In total, 20 single nucleotide polymorphisms (SNPs) in 17 previously reported psoriasis susceptibility loci and 34 SNPs from 24 previously reported SLE susceptibility loci were investigated in our initial psoriasis and SLE GWAS dataset. Among these SNPs, we selected two SNPs (rs8016947 and rs4649203) with association values of p<5×10(-2) for both diseases in the GWAS data for further investigation in psoriasis (7260 cases and 9842 controls) and SLE (2207 cases and 9842 controls) using a Sequenom MassARRAY system., Results: We found that these two SNPs (rs8016947 and rs4649203) in two loci (NFKBIA and IL28RA) were associated with psoriasis and SLE with genome-wide significance (Pcombined<5×10(-8) in psoriasis and Pcombined<5×10(-8) in SLE): rs8016947 at NFKBIA (Pcombined-psoriasis=3.90×10(-10), Pcombined-SLE=1.08×10(-13)) and rs4649203 at IL28RA (Pcombined-psoriasis=3.91×10(-12), Pcombined-SLE=9.90×10(-9))., Conclusions: These results showed that two common susceptibility loci (NFKBIA and IL28RA) are shared by psoriasis and SLE in the Chinese Han population.

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&#95;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.

Background: Punctate palmoplantar keratoderma (PPPK) is a rare autosomal dominant skin disorder characterised by numerous hyperkeratotic papules irregularly distributed on the palms and soles. To date, no causal gene for this disease has been identified., Methods: We performed exome sequencing analysis of four affected individuals and two unaffected controls from one Chinese PPPK family where disease locus was mapped at 8q24.13-8q24.21 by our previous linkage analysis., Results: We identified a novel heterozygous mutation in COL14A1 gene (c.4505C→T (p.Pro1502Leu)), which located within the linkage region that we previously identified for PPPK. The mutation was shared by the four affected individuals, but not for the two controls of the family. Sanger sequencing confirmed this mutation in another four cases from this family. This mutation was invisible in the normal controls of this family as well as the additional 676 unrelated normal controls and 781 patients with other disease. The shared COL14A1 mutation, p.Pro1502Leu, is a missense substitution at a highly conserved amino acid residue across multiple species., Conclusions: The power of combining exome sequencing and linkage information in the study of genetics of autosomal dominant disorders, even in simplex cases, has been demonstrated. Our results suggested that COL14A1 would be a casual gene for PPPK, which was helpful for advancing us on understanding of the pathogenesis of PPPK.