This document discusses genetic polymorphisms and summarizes several research articles. It begins by defining genetic polymorphisms as variations in regulatory DNA. It then summarizes a study that used a cross-species strategy to identify genes involved in Alzheimer's disease by comparing human and fly genomes. Another section summarizes findings from a study linking certain genes to membranous nephritis. Specifically, it discusses the association between this disease and the PLA2R receptor gene. The document concludes by discussing the medical utility of these findings, such as enabling early diagnosis and treatment.

1. Genetic polymorphismsCindyZuluaga RamírezMedicine studentMolecular Biology

2. FOLDING

3. FOLDING

4. INTRODUCTIONVariotion in regulatory DNA iswhatwecallPolymorphism.Thisisone of theways in wichwe can detect Polymorphisms.

5. Cross-Species Strategy Might Be a Powerful Tool for Studying Human DiseaseScienceDaily (Feb. 4, 2011)

6. Cross –speciesstrategy Specifically, the researchers evaluated 19 genes from 15 distinct genomic regions identified in a human GWAS designed to identify genes that influence Alzheimer´s disease pathology.

7. FINDINGS IN THE TECHNIQUE In six out of these 15 genomic regions, a causal gene was subsequently identified in the fly disease model on the basis of interactions with the neurotoxicity of Tau protein, a well-known constituent of AD pathology.

8. OBSERVATIONSI think that this technique is a huge improvement for genetic studies, since scientists are taking information from some other species in wich we could find some genetic similarities in some diseases and making new finds of the genetic basis of the disorder and get some new treatments .

9. Genes That Link Nephritis to Autoantibodies and Innate ImmunityTHE NEW ENGLAND JOURNAL OF MEDICINE (FEBRUARY 17,2011)

10. FINDINGS

11. The annual incidence of membranous nephropathy is approximately 1 case per 100,000 population.The results reported by Stanescu et al. confirm the findings of two recent studies from Asia (Taiwan and Korea) that used a candidate gene approach. Both those studies examined only SNPs in the PLA2R gene that resulted in amino acid changes, and a significant association was found for one SNP.

12. Although a relation between the HLA system and membranous nephropathy has been recognized for some time, the knowledge of an association between this disease and PLA2R is recent. In 2009, Beck and colleagues reported autoantibodies with specificity for PLA2R that were present in 70% of their patients with idiopathic membranous nephropathy but not in controls or patients with secondary membranous nephropathy. These results are now confirmed and extended in a letter by Debiec and Ronco in this issue of the Journal.

13. The SNP in the PLA2R gene with the strongest association does not alter the amino acid sequenceTwopossibletheoriesThers4664308 might be a marker for a rare variation in the protein sequence, below the threshold required to be considered a SNP. This putative variant would then confer a very high risk of disease for its carriers. the true association might not be with rs4664308 but rather with rs3749117, which is a nonsynonymous SNP reported to be in linkage disequilibrium with rs4664308. If so, the higher odds ratios in all three cohorts would have occurred at random.

14. CONCLUSSION In summary, this new genomewide association study highlights the interaction between the HLA system and the receptor for sPLA2 and provides substantial credence for a pathogenic role for the recently discovered autoantibodies in membranous nephropathy. It may redirect research toward finding a remedy for this troublesome disease.

15. OBSERVATIONSI think this new discovery will make easier the diagnosis of idiopathic membranous nephropathy making karyotype and searching changes among the alleles implicated in this disorder that encode HLA-DQA1 and the M-type phospholipase A2 receptor.

16. MEDICAL UTILITY

17. MEDICAL UTILITYEarly diagnosisImprovement in thelifequality of thepatientsEasy identification of the patients in riskEarly and quickbegining of treatmentForthedevelopment and thesustentation of geneticstudies .

18. BIBLIOGRAPHY N Engl J Med 2011; 364:679-680; http://www.nejm.org/doi/full/10.1056/NEJMe1014144 http://www.sciencedaily.com/releases/2011/02/110203124712.htmSTRACHAN, Tom. Human molecular genetics , 2004. 3.ed. Garland science