Solute Carrier Family 26, Member 3

Alternative Names

  • SLC26A3
  • Downregulated in Adenoma
  • DRA
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OMIM Number

126650

Gene Map Locus
7q31.1

Description

SLC26A3 (or DRA) is the major apical anion Na-independent exchanger mediating Cl(-) absorption in intestinal epithelial cells. SLC26A3 is primarily expressed in the apical brush border membrane of ileal enterocytes and colonic epithelium. Disturbances in SLC26A3 function and expression have been implicated in diarrheal conditions such as congenital secretory chloride diarrhea (DIAR1) and inflammatory bowel diseases.

Molecular Genetics

The SLC26A3 gene, located on chromosome 7q31.1, spans approximately 39 kb and comprises 21 exons. The encoded SLC26A3 protein is predicted to weigh 84-kD and to assume the role of a transcription factor or a protein that interacts with transcription factors.

Interestingly, SLC26A3 exhibits a high homology, with a similar genomic structure, to the SLC26A4 gene, located 3-prime and implicated in Pendred syndrome.

Epidemiology in the Arab World

View Map
Variant NameCountryGenomic LocationClinvar Clinical SignificanceCTGA Clinical Significance Condition(s)HGVS ExpressionsdbSNPClinvar
NM_000111.3:c.559G>TPalestine; United Arab...NC_000007.14:g.107791059C>APathogenicLikely Pathogenic, PathogenicDiarrhea 1, Secretory Chloride, CongenitalNG_008046.1:g.17175G>T; NM_000111.3:c.559G>T; NP_000102.1:p.Gly187Ter12191303216759

Other Reports

Kuwait

Höglund et al. (1998) examined the allelic diversity of congenital chloride diarrhea (CLD) in a cohort of five Kuwaiti families (five patients and six parents) who resided in Al Jahra district (240,000 out of 300,000 were Bedouins) and four Saudi families (five patients, three unaffected siblings, eight parents). In this cohort, the most common mutation was c.G559T in exon 5 of the SLC26A3 gene causing a protein change of p.G187X. Haplotypes segregating with the p.G187X mutation were well conserved proposing a founder effect for this mutation. Furthermore, population-historical data provided additional evidence for the founder effect of the p.G187X mutation by demonstrating Bedouins who resided in the deserts of the Arabian Peninsula as common ancestors for the majority of Kuwaiti and Saudi populations. Höglund et al. (1998) concluded that combining the founder effect and the high rate of consanguineous marriages (85%, of those 95% were parental-first-cousin marriages) led to the unusually high incidence of CLD and that determining the age of this major Arabic founder mutation was complicated in light of migration history and high rate of consanguinity.

Saudi Arabia

Höglund et al. (1998) examined the allelic diversity of congenital chloride diarrhea (CLD) in a cohort of five Kuwaiti families (five patients and six parents) who resided in Al Jahra district (240,000 out of 300,000 were Bedouins) and four Saudi families (five patients, three unaffected siblings, eight parents). In this cohort, the most common mutation was c.G559T in exon 5 of the SLC26A3 gene causing a protein change of p.G187X. Haplotypes segregating with the p.G187X mutation were well conserved proposing a founder effect for this mutation. Furthermore, population-historical data provided additional evidence for the founder effect of the p.G187X mutation by demonstrating Bedouins who resided in the deserts of the Arabian Peninsula as common ancestors for the majority of Kuwaiti and Saudi populations. Höglund et al. (1998) concluded that combining the founder effect and the high rate of consanguineous marriages (85%, of those 95% were parental-first-cousin marriages) led to the unusually high incidence of CLD and that determining the age of this major Arabic founder mutation was complicated in light of migration history and high rate of consanguinity.

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