ABSTRACT
Intronic microsatellites repeats were implicated in the pathogenic mechanisms of several diseases. SLC26A4 gene, involved in the genetic susceptibility of autoimmune thyroid disease (AITD), harbours large non-coding introns. Using the tandem repeat finder (TRF) Software, two new polymorphic microsatellite markers, rs59736472 and rs57250751, located at introns 10 and 20, respectively, were identified. A case-control design including 308 patients affected with AITD (146 GD, 90 HT and 72 PIM) and 212 unmatched healthy controls were performed for each marker (rs59736472, D7S2459 and rs57250751). Furthermore, we used PHASE 2.0 version to reconstruct haplotypes, Kolmogorov-Smirnov (KS) and the Clump analysis program for multivariate analysis. The fluorescent genotyping revealed three alleles (106,112 and 115 bp) for rs57250751 and 12 alleles for both D7S2459 and rs59736472 ranging from 134 to 156 bp and from 144 to 168 bp, respectively. The case-control analysis confirmed the positive association of D7S2459 with Hashimoto thyroiditis (HT) disease previously reported. Moreover, a significant association was found only with rs59736472 and HT disease. Haplotype-specific analysis showed that the 140-148-115 haplotype may increase the risk of HT (χ2=9.8, 1 df, P=0.0017, OR=2.07, IC [1.27-3.36]). Consequently, considering the number of repetitions of both D7S2459 and rs59736472, we found 15 alleles ranging from 45 to 59 repetitions. The case-control analysis showed a significant association of the 55 repetition with HT disease (χ2=6.32, 1 df, p c=0.012, OR=1.74, IC [1.1-2.76]). In conclusion, we suggest the association of longer alleles of intron 10 of SLC26A4 gene with HT disease.
Subject(s)
Hashimoto Disease/genetics , Introns/genetics , Membrane Transport Proteins/genetics , Microsatellite Repeats/genetics , Polymorphism, Single Nucleotide/genetics , Tandem Repeat Sequences/genetics , Adult , Case-Control Studies , Female , Genetic Predisposition to Disease , Genotype , Haplotypes/genetics , Humans , Male , Sulfate TransportersABSTRACT
Deleterious mutations of SLC26A4 cause Pendred syndrome (PS), an autosomal recessive disorder comprising goitre and deafness with enlarged vestibular aqueducts (EVA), and nonsyndromic hearing loss (NSHL). However, the SLC26A4 hyperactivity was recently associated with the emergence of autoimmune thyroid diseases (AITD) and asthma among human and mouse model. Here, by direct sequencing, we investigate the sequences of the 20 coding exons (2 to 21) of SLC26A4 and their flanking intron-exon junctions among patients affected with Graves' disease (GD) hyperthyroidism. Ten mono-allelic variants were identified, seven of which are intronic and previously unreported. Two, c.898A>C (p.I300L) and c.1061T>C (p.F354S), of the three exonic variants are non synonymous. The p.F354S variant is already described to be involved in PS or NSHL inheritances. The exploration by PCR-RFLP of p.I300L and p.F354S variants among 132 GD patients, 105 Hashimoto thyroiditis (HT), 206 Healthy subjects and 102 families with NSHL have shown the presence of both variants. The p.F354S variation was identified both among patients (1~HT and 3 GD) and healthy subjects (n=5). Whereas, the p.I300L variant was identified only in GD patients (n=3). Our studies provide evidence of the importance of systematic analysis of SLC26A4 gene sequences on models other than deafness. This approach allows the identification of new variants and the review of the pathogenic effects of certain mono-allelic variants reported responsible for PS and NSHL development.
Subject(s)
Graves Disease/genetics , Membrane Transport Proteins/genetics , Mutation, Missense , Point Mutation , Amino Acid Sequence , Animals , Base Sequence , Case-Control Studies , Female , Genetic Association Studies , Goiter, Nodular/genetics , Goiter, Nodular/pathology , Graves Disease/pathology , Hashimoto Disease/genetics , Hearing Loss, Sensorineural/genetics , Hearing Loss, Sensorineural/pathology , Humans , Male , Molecular Sequence Data , Sequence Alignment , Sulfate TransportersABSTRACT
FOXE1 polyalanine tract (poly-Ala) has been associated with thyroid dysgenesis. Recently, the SNP (rs1867277:-238G>A) within the FOXE1 5'UTR was involved in the genetic susceptibility to thyroid cancer (TC). In the aim to assess the influence of FOXE1 poly-Ala length on the genetic susceptibility to TC and autoimmune thyroid diseases (AITD), a case-control design (including 261 Tunisian AITD, 170 Spanish TC and respectively 171 and 218 matched healthy subjects) was performed. The effect of Ala length and rs1867277 alleles on FOXE1 expression was investigated by mRNA relative real time quantification on 8 papillary thyroid carcinoma (PTC) and 10 Graves' disease (GD) genotyped thyroid biopsies. The fluorescent genotyping of poly-Ala polymorphism revealed nine alleles (from 12 to 22 repetitions). The association of poly-Ala polymorphism with AITD was rejected (Pc>0.05). However, a significant association was found with TC. In addition, the genotypic distributions revealed the predispositional effect of the 16/16 genotype (OR = 2.71; 95%CI: 1.36-5.42; p=0.001) and the protector effect of the 14/14 genotype (OR= 0.46; 95%CI: 0.29-0.72; p=0.003). The quantification studies reveal that FOXE1 transcripts were less abundant in PTC than GD samples. Moreover, FOXEI gene was 4,8 fold less expressed among PTC protected patients compared to homozygous 16/16-A/A. In conclusion, by exploring the poly-Ala polymorphism, we confirmed the involvement of {\it FOXE1} gene in the genetic susceptibility to TC and we reported its down expression among PTC tissues.
