Both alleles of the M235T polymorphism of the angiotensinogen gene can be a risk factor for myocardial infarction.

We have studied the role of three polymorphic genes of the renin-angiotensin system (RAS) as independent risk factors for myocardial infarction (MI) and their correlation with three of the major coronary risk factors: serum cholesterol (CH), hypertension (HT) and smoking (SM). A population of 392 men was genotyped for the M235T polymorphism of the angiotensinogen (AGT) gene, the insertion/deletion of the angiotensin-converting enzyme (ACE) and the all66c of the angiotensin-II type 1 receptor (AT1R), by means of polymerase chain reaction (PCR) and restriction enzyme analysis. It was observed that the T allele frequency increased significantly in the MI with HT, CH, and SM subgroup (0.58 vs 0.31) (p<0.01). In contrast, the M allele frequency was higher in the MI without HT, CH, and SM (0.69 vs 0.42) (p<0.01). A strong association between the MM genotype and MI (p<0.001, odds ratio=4.29, confidence interval=1.95-9.42) was found when age-matched MM control subjects were compared to MI individuals with none of the other known major coronary risk factors. Futhermore, subjects with the MM genotype showed a significantly higher plasma renin activity (PRA) profile than those with the TT genotype (p<0.001). It can be concluded that the M allele is an independent risk factor for MI and the T allele modified the risk when other major risk factors are present.

The genotype interactions of methylenetetrahydrofolate reductase and renin-angiotensin system genes are associated with myocardial infarction.

We analyzed the evolution with age of the frequencies of the I/D polymorphism of the angiotensin I-converting enzyme (ACE), a1166c of the angiotensin II AT1 receptor (AT1R), M235T of the angiotensinogen (AGT) and A225V of their methylenetetrahydrofolate reductase (MTHFR) gene in a healthy (H) population and the subsequent comparison to age- and sex-matched groups of myocardial infarction (MI) subjects. A total of 472 H subjects were divided into three groups < 30, 30-55 and > 55 years old and 277 individuals with MI into two groups 30-55 and > 55 years old. The evolution with age showed that the AGT M allele (P < 0.001) and the MTHFR V allele (P < 0.05) frequency decreased with age in H men. The comparison between healthy and MI groups showed that the MM genotype frequency increased in MI men > 55 years (OR =4.16; 95% CI; 1.72-10.1) The cc genotype showed a similar behaviour (OR = 3.96; 95% CI; 1.21-12.9). In men, all the combinations with MM genotype presented a high risk, with OR values between 1.10 and 7.22. In women, the cc genotype increased in the MI > 55 group (OR = 6.66; 95% CI; 2.02-21.9). All the combinations with the cc genotype showed OR values between 1.71 and 13.3. The MM genotype in men and cc genotype in men and women, are independent risk factors for MI. We propose that the study of the allele frequency evolution in an H population at different ages is essential to determine risk factors for MI in case-control studies, since data from isolated age-matched groups can be misinterpreted.

[Myocardiopathies (II). Genetic changes in the etiopathogenesis of hypertrophic myocardiopathy. The therapeutic prospects]. / Miocardiopatías (II). Alteraciones genéticas en la etiopatogenia de la miocardiopatía hipertrófica. Perspectivas terapéuticas.

The genetical characterization of any disease implies its immediate theoretic and practical reorganization since all the basic clinical aspects such as ethology, diagnosis, prognosis, prevention and finally treatment are affected. This can be the fact for hypertrophic myocardiopathy in the near future. Recently, mutations in some new genes causing this alteration, apart from those found in the beta-myosin heavy chain gene, have been identified. Hypertrophic cardiomyopathy could be classified etiopathogenetically as primary, if it is due to a genetic alteration in any of the components of the sarcomere, and secondary when the initial factor is external, although it will be eventually reflected in a malfunction of the sarcomere. Therefore hypertrophic cardiomyopathy could be defined as a myocardial disorder with and autosomic hereditary pattern which is characterized by a ventricular hypertrophy due to alterations in the cardiac sarcomere. Detected mutations so far, which have been admitted to be the primary alteration in this disease, are localized in the beta-myosin heavy chain gene (14q1), in the alpha-tropomyosin gene (15q2), in the cardiac troponin T gene (1q3), as well as in the chromosome 11 p13-q13 loci. Different authors have pointed out a possible epigenetic mechanism produced by endogenous or environmental secondary factors as responsible for hypertrophic myocardiopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

[Echocardiographic diagnosis of pulmonary valve calcification]. / Diagnóstico ecocardiográfico de la calcificación valvular pulmonar.

Calcification of the pulmonary valve is a uncommon condition. Non invasive diagnostic methods such as M-mode and two dimensional echocardiography have facilitated the identification of vegetations and calcifications on the pulmonary valve. Very few cases of isolated calcification on the pulmonary valve have been reported; a previous lesion of the valve almost always exists. The purpose of this communication is to report two cases with calcification of pulmonary valves without underlying pathology and to highlight the great utility of echocardiography in diagnosis and follow-up of such cases.