IVS4-14 A/G and IVS4-73 C/T polymorphisms in OLR1 gene in patients with ischemic cerebrovascular diseases.

INTRODUCTION: Oxidized low-density lipoprotein (ox-LDL) plays a key role in the processes of atherogenesis, the major cause of myocardial infarction. Increased levels of ox-LDL relate to plaque instability in human coronary atherosclerotic lesions. Moreover, ox-LDL levels show a direct correlation to the severity of coronary syndromes. Most of these effects are mediated by the interaction of ox-LDL with its major receptor, named LOX-1, that is encoded by OLR1 gene. AIMS AND METHODS: In the present study, we examined the prevalence of OLR1 gene polymorphisms, IVS4-14 A/G and IVS4-73 C/T, which regulate the expression of LOXIN, in patients with ischemic cerebrovascular diseases (ICVD). We studied 43 consecutive patients (males = 19; females = 24) aged 26 to 65 years. All the patients were from the same geographical area. They were affected by ICVD. The control group comprised 69 healthy blood donors, with age and sex comparable to those of the patients. RESULTS: The distribution of G/G genotype and A/G genotype was statistically significant between patients and controls (chi(2) = 5.87, p = 0.01 and chi(2) = 4.33, p = 0.04, respectively). CONCLUSION: These preliminary data would suggest that in ICVD patients the LOX-1 isoform that induces internalization of ox-LDL is more frequent and a cascade of events responsible for endothelial dysfunction and injury. LOX-1 might play a fundamental role in the initiation and progression of atherosclerosis and have a significant role in the pathogenesis of ICVD. Therefore, the patients with G homozygosity for IVS4-14 polymorphism and T homozygosity for IVS4-73 polymorphism have higher risk to develop ICVD. Future studies are warranted to assess whether the analysis of polymorphisms may be useful for the clinical approach to evaluate risk factors for atherosclerosis and related disorders.

I219V polymorphism in hMLH1 gene in patients affected with ulcerative colitis.

INTRODUCTION: hMLH1 gene, lying on chromosome 3p21-23, is a key factor of the mismatch repair (MMR) complex, which amends DNA replication errors. MMR alterations are involved in the development of both hereditary and sporadic forms of colorectal carcinoma related to ulcerative colitis (UC). I219V Polymorphism is located on exon 8 of hMLH1 and provides an aminoacidic substitution of isoleucine to valine, on the protein codon 219. This may affect the speed and fidelity of protein synthesis because of a tRNA paucity or changes in the mRNA secondary structure. Most of the hereditary nonpolyposis colon cancer-associated missense mutations of hMLH1 cause structural changes of the amino- or carboxy-terminal regions, involving the domains that interact with ATP and hPMS2. AIMS AND METHODS: In this study, we analyzed the hMLH1 I219V polymorphism frequency in colectomized patients with UC. Venous blood from 100 ulcerative patients and 97 apparently healthy subjects has been collected. Out of 100 patients affected with UC, 75 noncolectomized showed an alternating course of disease, while 25 did not respond to the common drugs, and underwent colectomy. Genotyping was performed by polymerase chain reaction and following enzymatic digestion by BccI. RESULTS: No significant differences were found between patients with UC and controls both for genotype and allele frequencies. However, our data show a significant association when colectomized and noncolectomized patients are compared. The frequencies of G homozygosity were 28% in colectomized and 10.7% in noncolectomized patients (p < 0.05, chi(2) = 4.4, Odds ratio = 3.3). The allele frequencies of allele A were 52% in colectomized and 68% in noncolectomized patients; while those of allele G were 48% and 32%, respectively. CONCLUSIONS: I219V polymorphism in hMLH1 could influence the clinical course of the disease and lead to resistance to therapy.