Neus Valveny

APO E Polymorphism in Spanish and Moroccan populations

Apolipoprotein E (apoE) gene polymorphism was analyzed by polymerase chain reaction in one Moroccan and six Spanish populations, a total of 660 individuals. No significant differences were observed between samples, and the mean relative frequencies (with 95% confidence intervals) found were 0.104 (0.069–0.139) for the e4 allele, 0.855 (0.813–0.897) for e3 and 0.041 (0.015–0.067) for e2. Frequencies of the e4 allele were low in comparison to Northern European populations, but similar to those reported for other South‐European populations. The presence of a rare mutation, E2 Christchurch, in one Basque individual was confirmed by sequence analysis.

Angiotensin I converting enzyme polymorphism in humans with age-associated memory impairment: relationship with cognitive performance.

We compared the distribution of an insertion (I)/deletion (D) polymorphism coding for the angiotensin I converting enzyme (ACE) gene in 100 subjects fulfilling NIMH criteria for Age-associated memory impairment (AAMI) and 124 controls. We found significantly reduced prevalences of the ACE I/I genotype together with increases of the ACE D allele in the AAMI group. We further compared the neuropsychological performance of the AAMI group according to their ACE genotype. Those AAMI subjects presenting the ACE I/I genotype exhibited better performance on a measure of frontal lobe function. Our results suggest that the lack of the ACE I/I genotype and the presence of the ACE D allele are associated with memory impairment in the elderly.

Neuropsychological and Genetic Differences Between Age‐Associated Memory Impairment and Mild Cognitive Impairment Entities

OBJECTIVE: To neuropsychologically and genetically compare age‐associated memory impairment (AAMI) and mild cognitive impairment (MCI) entities and to determine what proportion of AAMI diagnosed individuals could also receive a MCI diagnosis. To compare the distribution of a previously known genetic risk factor for Alzheimers disease (apolipoprotein E common polymorphism) associated with these two conditions with a sample of the normal aging.

Apo E influences declarative and procedural learning in age-associated memory impairment.

Age-associated memory impairment (AAMI) is a clinical entity which was originally described to define memory problems linked to normal aging. Apolipoprotein E and ACE genes have both been associated with cognitive impairment in aging and dementia. The purpose of this study was to investigate memory and executive functions in AAMI according to the genetic background. We found that subjects carrying the Apo E epsilon4 allele exhibit lower memory performance on tests of both declarative and procedural memory. We did not find differences on frontal lobe tests. These findings give further support to the hypothesis concerning a genetic susceptibility for cognitive impairment in aging.

Genetic study of the population of Tenerife (Canary Islands, Spain): Protein markers and review of classical polymorphisms

Data on six protein polymorphisms (19 alleles) from the human population of Tenerife are presented and discussed along with other classical markers in relation to the origin of the Canarians. Genetic influences from three population groups were considered: the Iberians, and the Berbers and non-Berbers (Arabs) from north Africa. The systems examined show the Tenerife population lies within the limits of variation described for various Iberian groups, with a slight tendency towards the characteristics of north African populations. When blood groups, red cell enzymes and serum protein data were considered, the similarity of the Canary population to Iberians seems strengthened (70% estimated contribution of Iberian peninsula genes to the present-day Canarian pool), while some relation with north African groups is shown. Genetic distances between Canarians and Arabs and Canarians and Berbers are lower than those between the two north African groups, indicating a relative and comparable contribution of each to the present-day gene pool of the Canarian population. The Arab contribution could be attributable to the slaves who were introduced to these islands after the conquest in the 15th century, while the Berber contribution could be the remnants of the extinct aboriginal peoples of the islands (Guanches) or a more recent immigration due to slavery. Genetic data do not allow us to distinguish between these two possibilities.

Lack of association between eNOS gene polymorphisms and ischemic heart disease in the Spanish population.

Through the nitric oxide (NO) production in the vascular system, the endothelial nitric oxide synthase (eNOS or NOS3) is a key enzyme in blood pressure regulation and atherosclerosis control. Several previous studies have suggested an important role of eNOS as a genetic risk factor for cardiovascular diseases. In this context, a genetic association study was carried out between two eNOS polymorphisms (the ecNOS4a/b VNTR and the G894T substitution) in a sample of 101 nuclear families having one affected offspring of ischemic heart disease (IHD). Transmission disequilibrium test (TDT) revealed partial associations between the VNTR marker and IHD in patients with a type A behavior pattern (TABP) (P = 0.0325, RR = 3.67) and for the haplotype formed by variant b of the VNTR and the T mutation of the G894T substitution in the IHD‐affected subgroup having body mass index (BMI) lower than 25 (P = 0.0348, RR = 0.22). However, once multiple testing correction was applied, the associations became nonsignificant. A significant effect of the haplotype b‐G increasing high‐density lipoprotein cholesterol (HDL‐C) plasma levels was detected (P = 0.021 after Bonferroni correction). From a population point of view, frequencies found for G894T substitution in Spain were significantly different from other populations.

APOE and APOC1 genetic polymorphisms in age-associated memory impairment

Abstract We studied the distribution of two genetic polymorphisms (APOE and APOC1) in a sample of 100 subjects fulfilling the NIMH criteria for age-associated memory impairment (AAMI) and 124 controls. We found significant associations both for APOE and APOC1 loci and their combinations with the AAMI condition. The findings in our sample suggest that memory-impaired subjects as described by the NIMH may be genetically differentiated from normally aging subjects in relation to these two polymorphisms and indicate the interest of considering variations in the APOC1 gene for further studies in cognitive aging.

Spanish and African contribution to the genetic pool of the Canary islanders: data from GM and KM haplotypes and RFLPs in the immunoglobulin IGHG loci

Data on the GM and KM haplotypes and RFLPs in the immunoglobulin IGHG loci are reported intending to evaluate the genetic contribution of the different populations (Europeans and Africans) who settled Tenerife Island. The GM and KM allotypic systems reveal an estimated European genetic admixture of 88%. The only possible African contribution is the presence of the GM*1,17;..;5* haplotype (2.5%), but no other traces of Black African characteristic haplotypes are found. Although new RFLP haplotypes are described, DNA variation is similar to that reported in Caucasoids with a marked absence of restriction fragments characteristic of Black Africans.

Lack of association between methylenetetrahydrofolate reductase (MTHFR) C677T and ischaemic heart disease (IHD): family-based association study in a Spanish population.

The effect of the C677T polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene, traditionally associated with ischaemic heart disease (IHD), was assessed in a Spanish population. The transmission disequilibrium test (TDT) was used to determine a possible association in a sample of 101 trios of IHD patients. The distribution of MTHFR genotypes was similar in the IHD subjects and the parental group; the TT genotype was present in 14.9% of IHD patients, as compared to 15.2% in the parents. The frequency of the T allele was also similar in IHD cases and parents (39.6% vs. 42.4%; p = 0.649). The TDT confirmed that the observed transmission of the T allele did not deviate significantly from the expected one (χ2 = 0.743; p > 0.4). Our TDT analysis clearly demonstrates a lack of association between the T allele of the C677T mutation in MTHFR and cardiovascular artery disease, both for the general group and for different risk subgroups (smokers, hypertension, male sex, overweight and type A behaviour pattern) in the Spanish population.

E65 K polymorphism in KCNMB1 gene is not associated with ischaemic heart disease in Spanish patients

AbstractHypertension is a main risk factor for atherosclerosis through vascular wall hyperplasia. A recent study reported a new polymorphism (E65 K) in the β1 subunit (KCNMB1) gene of the Ca2+-dependent potassium channel with a protective effect against the severity of diastolic hypertension, but further data have lead to conflicting results. In order to ascertain the involvement of the E65 K variant in cardiovascular system regulation, the potential association between this mutation and ischaemic heart disease was assessed through a family-based association study (n=302 individuals). Transmission disequilibrium analysis failed to detect any association between this polymorphism and ischaemic heart disease. Although a minor effect cannot be discarded, sample analytical power and negative results do not support a major role for E65 K polymorphism in atherogenic pathologies.