Biomedical subjects

Marian M de Pancorbo

Publications and source records attributed to Marian M de Pancorbo.

6 recordsLinked to original sources

PubMed2006

Sequence polymorphisms of the mtDNA control region in a human isolate: the Georgians from Swanetia.

In this work, we analyzed the sequence diversity of the mtDNA control region (HVI and HVII) in a sample of 48 individuals from Swanetia (Georgia), using direct fluorescent-based sequencing methods. We identified 43 different mtDNA haplotypes resulting from 78 polymorphic sites (46 in HVI and 32 in HVII). Most of the variable positions identified in both HVI and HVII were transitions (82.6 and 71.9%, respectively). The frequency of length heteroplasmy in the homopolymeric C-stretch regions was the same for both segments (10.4%). The sequence diversity increased markedly when both hypervariable regions were analyzed jointly (HVI: 0.985, HVII: 0.975, HVI+HVII: 0.994). Accordingly, the probability of two randomly selected sequences matching (random match probability, RMP) decreased from 3.4% (HVI) to 2.6% (HVI+HVII), despite which the RMP values in Georgians remained higher than estimated in most Europeans. This suggests that the variability of maternal lineages tends to be lower in traditional human isolates and, therefore, the potential of discrimination of mtDNA in forensic analysis is more limited in this type of population. The incorporation of HVII data also contributed to the refinement of results regarding the genetic relationships among the samples included in the analyses, which stress the importance of considering HVII in both population and forensic genetics.

Base Sequence↗

PubMed2005

Polymorphism in the cholesterol 24S-hydroxylase gene (CYP46A1) associated with the APOEpsilon3 allele increases the risk of Alzheimer's disease and of mild cognitive impairment progressing to Alzheimer's disease.

BACKGROUND: Late-onset Alzheimer's disease (LOAD) is associated with changes in certain proteins, such as ApoE and Cyp46A1, of the elimination route for cerebral cholesterol. The main lipoprotein involved in its transport is ApoE whose Epsilon4 allele is the least efficient. However, the presence or absence of this allele does not determine the development of LOAD, which implies the existence of other susceptibility factors associated with the disease, such as the CYP46A1 gene that encodes the enzyme cholesterol 24S-hydroxylase. OBJECTIVE: To find new data to contribute to the evaluation of whether the presence of the T allele in the polymorphic site rs754203 of the CYP46A1 gene leads to a greater risk of developing mild cognitive impairment (MCI) and LOAD. Furthermore, given the link between APOE and CYP46A1, we proceeded to relate both genotypes in each of the patient groups studied. METHODS: We studied MCI and LOAD patients and also carried out an analysis of those MCI patients who progressed from a mild cognitive deterioration to a clinically evident Alzheimer's disease during the study. RESULTS: The frequency of the CYP46A1-T allele in the LOAD patients with APOEpsilon3 alleles is significantly higher with respect to the control group; the same occurs in the group made up of LOAD patients together with the MCI patients who progressed to LOAD. The risk of developing LOAD when this allelic combination exists is 2.262 times higher (95% CI 1.337-4.202). However, having the CYP46A1-T allele does not increase the risk of suffering from LOAD in carriers of the APOEpsilon4 allele, probably because the transport of cholesterol is already affected in such patients and possibly masks the effect of the CYP46A1-T allele. CONCLUSIONS: The CYP46A1-T allele increases the risk of suffering from LOAD in persons carrying the APOEpsilon3 allele.

Aged↗

PubMed2005

Microsatellite data support subpopulation structuring among Basques.

Genomic diversity based on 13 short tandem repeat (STR) loci (D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820, D16S539, TH01, TPOX, and CSF1PO) is reported for the first time in Basques from the provinces of Guipúzcoa and Navarre (Spain). STR data from previous studies on Basques from Alava and Vizcaya provinces were also examined using hierarchal analysis of molecular variance (AMOVA) and genetic admixture estimations to ascertain whether the Basques are genetically heterogeneous. To assess the genetic position of Basques in a broader geographic context, we conducted phylogenetic analyses based on F(ST) genetic distances [neighbor-joining trees and multidimensional scaling (MDS)] using data compiled in previous publications. The genetic profile of the Basque groups revealed distinctive regional partitioning of short tandem repeat (STR) diversity. Consistent with the above, native Basques clearly segregated from other populations from Europe (including Spain), North Africa, and the Middle East. The main line of genetic discontinuity inferred from the spatial variability of the microsatellite diversity in Basques significantly overlapped the geographic distribution of the Basque language. The genetic heterogeneity among native Basque groups correlates with the peculiar geography of peopling and marital structure in rural Basque zones and with language boundaries resulting from the uneven impact of Romance languages in the different Basque territories.

DNA↗

PubMed2005

Ancestral origins of the prion protein gene D178N mutation in the Basque Country.

Fatal familial insomnia (FFI) and familial Creutzfeldt-Jakob disease (fCJD) are familial prion diseases with autosomal dominant inheritance of the D178N mutation. FFI has been reported in at least 27 pedigrees around the world. Twelve apparently unrelated FFI and fCJD pedigrees with the characteristic D178N mutation have been reported in the Prion Diseases Registry of the Basque Country since 1993. The high incidence of familial prion diseases in this region may reflect a unique ancestral origin of the chromosome carrying this mutation. In order to investigate this putative founder effect, we developed "happy typing", a new approach to the happy mapping method, which consists of the physical isolation of large haploid genomic DNA fragments and their analysis by the Polymerase Chain Reaction in order to perform haplotypic analysis instead of pedigree analysis. Six novel microsatellite markers, located in a 150-kb genomic segment flanking the PRNP gene were characterized for typing haploid DNA fragments of 285 kb in size. A common haplotype was found in patients from the Basque region, strongly suggesting a founder effect. We propose that "happy typing" constitutes an efficient method for determining disease-associated haplotypes, since the analysis of a single affected individual per pedigree should provide sufficient evidence.

Amyloid↗

PubMed2005

Genetic polymorphisms at 13 STR loci in autochthonous Basques from the province of Alava (Spain).

In this study, allelic frequencies of the CODIS core short tandem repeat (STR) loci were estimated in a population sample consisting in 101 unrelated healthy autochthonous individuals from the Basque province of Alava (Northern Spain). Frequency distributions for all 13 STR loci were obtained using the AmpFlSTR Profiler Plus and AmpFlSTR COfiler amplification kits. The allelic frequencies generated were employed to calculate genetic and forensic useful parameters.

DNA↗

PubMed2003

5-Hydroxytryptamine 6 receptor (5-HT(6)) receptor and apolipoprotein E (ApoE) polymorphisms in patients with Alzheimer's disease in the Basque Country.

Although there is considerable evidence implicating apolipoprotein E (ApoE) epsilon4 in the development of the Alzheimer's disease (AD), additional factors are also known to be involved. Thus, an association has been described between C267T polymorphism of the 5-hydroxytryptamine 6 receptor (5-HT(6)) receptor gene and AD. This case-control study analyzes the ApoE and 5-HT(6) receptor polymorphisms in 173 cases and 102 age and sex matched controls from Araba and Bizkaia (The Basque Country, Spain). The analysis of ApoE showed the frequencies of epsilon4 allele to be significantly higher in AD patients (0.292) than in the controls (0.083). When 5-HT(6) receptor polymorphism was analyzed, a greater frequency of 267C allele was observed in AD patients than in controls, though the difference was not statistically significant. Likewise regarding ApoE epsilon4 status, no statistically significant difference was observed. In conclusion, the association of ApoE epsilon4 to AD in a sample of patients from the Basque Country is confirmed, though the association to C267T polymorphism of the 5-HT(6) receptor has not been observed.

Aged↗