A Study of GluK1 Kainate Receptor Polymorphisms in Down Syndrome Reveals Allelic Non-Disjunction at 1173(C/T). Issue 2 (21st May 2013)

• Record Type: Journal Article
• Authors: Ghosh, Debarati; Sinha, Swagata; Chatterjee, Anindita; Nandagopal, Krishnadas
• Is Part Of: Disease markers. Volume 27:Issue 2(2009)
• Page Start: 45
• Page End: 54
• Publication Date: 2013-05-21
• Subjects: Down syndrome -- mental retardation -- glutamate -- GluK1/GluR5/GRIK1 -- allelic non-disjunction -- parent and stage of origin -- risk; Diagnosis -- Periodicals; Biochemical markers -- Periodicals; Pathology -- Periodicals; 616
• DOI: 10.3233/DMA-2009-0647
• Languages: English
• ISSNs: 0278-0240

Abstract

Abstract : Mechanisms underlying Down syndrome (DS)-related mental retardation (MR) remain poorly understood. In trisomic offspring, non-disjunction may result in the reduction to homozygosity of a susceptibility allele inherited from a heterozygous parent. Accordingly, we sought evidence for allelic non-disjunction in the GluK1 gene that encodes the critical kainite-binding glutamate receptor subunit-5, maps to chromosome 21q22.1 in the DS critical region and is expressed in brain regions responsible for learning and memory. Three polymorphisms of GluK1 [522(A/C) rs363538; 1173(C/T) rs363430 and 2705(T/C) rs363504] were genotyped in 86 DS patient families by means of PCR-coupled RFLP assays and evaluated with respect to allele frequency, heterozygosity, linkage disequilibrium, stage and parental origin of allelic non-disjunction. We report that the distribution of allele frequencies is in Hardy-Weinberg equilibrium. Moderate heterozygosity (0.339) and a major allele frequency of 0.78 render the 1173(C/T) marker informative. Pair-wise comparisons reveal that 522(A/C)-1173(C/T) [ χ 2 = 31.2, df = 1, p = 0.0001; D ' = 0.42] and 1173(C/T)-2705(T/C) [ χ 2 = 18.3, df = 1, p = 0.0001; D ' = 0.34] are in significant linkage disequilibrium of weak magnitude. The estimated ratio of meiosis-I to meiosis-II errors arising from allelic non-disjunction of 1173(C/T) is 4:1 in maternal cases and 2:1 in paternal cases. Studies including additional markers and patient samples are warranted to further substantiate present findings.