The family reported to have X-linked Dyggve-Melchior-Clausen syndrome instead has X-linked SEDT caused by a novel TRAPPC2 frameshift variant.

The family reported to have X-linked Dyggve-Melchior-Clausen syndrome instead has X-linked SEDT caused by a novel TRAPPC2 frameshift variant.

Systematic molecular analysis of hemophilia A patients from Colombia.

Hemophilia A (HA) is an X-linked recessive disorder and the second most common coagulation disorder with an incidence of 1 in 5,000 live born males. Worldwide, there are 178,500 affected individuals, 60% with the severe form of the disease. Intron 22 and 1 inversions (Inv22 and Inv1) are the most frequent molecular alterations found in severe HA patients with a frequency of 45-50% and 0.5-5%, respectively. We have implemented a systematic cost-effective strategy for the identification of the molecular alteration in HA patients using Inverse shifting-PCR for Inv22 and Inv1, followed by the analysis of the F8 gene coding region by means of high resolution melting (HRM) PCR and Sanger sequencing in Inv22 and Inv1 negative patients. A total of 33 male HA patients and 6 women were analyzed. Inversion 22 was detected in 14/33 male patients (42.4%), 3/33 (9.1%) had Inv1, 3/33 (9.1%) had large structural variants, and 11/33 (33.3%) single nucleotide/ small frameshift variants. No genetic variant was found in 2/33 patients (6%). With this systematic approach we detected pathogenic variants in 31 out of 33 male affected individuals (94%) tested for the first time.in a cohort of patients from Colombia.

The impact of smoking on disease activity, disability, and radiographic damage in rheumatoid arthritis: is cigarette protective?

The ojective of this study is to assess the effect of tobacco smoking on disease activity, functional ability, and joint damage in a cohort of patients with early onset rheumatoid arthritis (EORA). 129 EORA patients attending the Rheumatology Unit of the School of Medicine of the "Universidad Nacional de Colombia" and the "Clínica de Artritis y Rehabilitación" in Bogota, Colombia, were enrolled in a prospective observational cohort study with 3-year follow-up. Clinical, biological, immunogenetics, and radiographic data were analyzed. Active disease was defined as DAS28 > 2.6. Smoking status was assessed by self-report as "never smokers" and "ever smokers". Patient groups with different smoking status were compared for RA measures. Status as "never smokers" and "ever smokers" was reported by 81.3 and 18.7%. Ever smokers had less risk of disability (HAQ-DI ≥ 0.5) at 36 month (Ever smokers vs. Never smokers OR for HAQ ≥ 0.5 0.25, 95% CI 0.06-0.97, p = 0.04). When former smokers were excluded in analysis, we found that current smoking was also associated with less disability and less risk of active disease. The percentage of erosive disease, radiographic progression, and SvdH score were similar in all smoking categories. In Colombian patients with EORA, smoking was associated with less disease activity and disability. Radiographic joint damage progressed at an equivalent rate in smokers and non-smokers. These data suggest a more benign, or at least not deleterious clinical course in smokers with RA.

The Role of 25-Hydroxyvitamin D as a Predictor of Clinical and Radiological Outcomes in Early Onset Rheumatoid Arthritis.

OBJECTIVE: The aims of this study were to compare the levels of 25-hydroxyvitamin D (25(OH)D) in patients with early-onset rheumatoid arthritis (EORA) versus a healthy control group and to assess the association of 25(OH)D deficiency and the BsmI polymorphism of the vitamin D receptor gene with clinical, radiological, and laboratory parameters. METHODS: Early-onset RA Colombian patients were enrolled in a 3-year follow-up study. Vitamin D deficiency was diagnosed for 25(OH)D levels of less than 20 ng/mL. Pearson and Spearman correlation coefficients were used to assess data. RESULTS: Seventy patients and 70 matched healthy subjects were included. 25-Hydroxyvitamin D was lower in the EORA group (27.13 [SD, 13.4] ng/mL vs. 33.74 [SD, 16.7] ng/mL; P = 0.01); 31.4% of EORA patients were vitamin D deficient. Remission was higher in subjects without 25(OH)D deficiency (22.7% vs. 47.9%; P = 0.04). Patients with 25(OH)D deficiency at baseline had higher Health Assessment Questionnaire and Physician Global Disease Activity Assessment scores, fatigue levels, erythrocyte sedimentation rate, and morning stiffness after 3 years. At disease onset, only a relationship between 25(OH)D deficiency with fatigue and morning stiffness was found. Neither radiographic progression nor Sharp van der-Heidje score was associated to hypovitaminosis D after 36-month follow-up. The bb genotype was less frequent in patients with vitamin D deficiency (0% vs. 16.6%; P = 0.04). Patients with BB-Bb genotype had lower 25(OH)D and a propensity to more severe disease. CONCLUSIONS: Our data provide further support for a role of vitamin D as a clinical biomarker for RA. Baseline 25(OH)D could have potential as a predictor of disease severity in EORA.

Association Analysis of Polymorphisms in TOMM40, CR1, PVRL2, SORL1, PICALM, and 14q32.13 Regions in Colombian Alzheimer Disease Patients.

OBJECTIVE: We evaluated the association of several single-nucleotide polymorphisms in different genes including APOE, TOMM40, CR1, PVRL2, SORL1, PICALM, and GWA_14q32.13 in a Colombian sample of Late-Onset Alzheimer disease (LOAD) patients. METHODS: A case-control study was conducted in 362 individuals (181 LOADs and 181 controls) to determine the association of single-nucleotide polymorphisms in APOE (e2, e3, and e4), TOMM40 (rs2075650), CR1 (rs665640), PVRL2 (rs6859), SORL1 (rs11218304), PICALM (rs3851179), and GWA_14q32.13 (rs11622883) with LOAD in a sample from Colombia. RESULTS: We were able to confirm the previously reported association of the APOE4 allele with AD. In addition, we report a new significant association with rs2075650 of TOMM40 for LOAD in our sample. We did not detect any significant interaction between TOMM40 and APOE4 carriers (heterozygous or homozygous) for disease risk development. However, Kaplan-Meier survival analyses suggest that AD patients with TOMM40 allele rs2075650-G have an average age of disease onset of 6 years earlier compared with carriers of the A allele. In addition, the age of disease onset is earlier if APOE4/4 is present. CONCLUSION: Our findings suggest that rs2075650 of TOMM40 could be involved in earlier presentation of LOAD in the Colombian population.

Comparative study of elderly-onset rheumatoid arthritis and young-onset rheumatoid arthritis in a Colombian population: clinical, laboratory and HLA-DRB1 findings.

OBJECTIVES: Elderly-onset rheumatoid arthritis (EORA) is considered to have different features in relation to young-onset rheumatoid arthritis (YORA). However, results from different evaluated populations worldwide have been inconsistent and in Colombia there are no known descriptions of the differences between these pathologies. The aim of this paper is to compare the clinical, laboratory and immunogenetic features in a Colombian population suffering with EORA and YORA. METHODS: EORA (≥65, n=104) and YORA (<65, n=96) patients were compared regarding clinical, laboratory and HLA-DRB1 alleles features. A control group without rheumatoid arthritis over 65 (n=179) was used to compare the HLA-DRB1 alleles. All patients met the ACR/1987 criteria for rheumatoid arthritis and the clinimetric index was calculated. RESULTS: The gender ratio (female/male) was 1.8:1 in EORA. In both groups, the main onset pattern of disease was an insidious polyarticular onset (p=0.35). EORA was characterised by more distal-proximal joint involvement in comparison to YORA (p=0.0007). In EORA, the rheumatoid factor and anti-cyclic citrullinated peptide (anti-CCP) antibodies frequency was close to 50%, lower than in YORA (63%). In both groups, the DAS28 and HAQ-DI score was higher than 6 and 1, respectively. The HLA-DRB1*0403 and *1402 frequency was significantly higher in EORA than in YORA. Also, the shared epitope (p=0.0392), HLA-DRB1*01 (p=0.0068) and *0101 (p=0.0151) were associated with an anti-CCP positivity and the HLA-DRB1*0403 is protective for the anti-CCP presence in EORA (p=0.0201). CONCLUSIONS: EORA is characterised by a different clinical presentation and HLA-DRB1 alleles with respect to YORA. HLA-DRB1*0403 and *1402 are significantly more frequent in EORA compared to YORA.

Mitochondrial DNA (mtDNA) haplogroups in 1526 unrelated individuals from 11 Departments of Colombia.

The frequencies of four mitochondrial Native American DNA haplogroups were determined in 1526 unrelated individuals from 11 Departments of Colombia and compared to the frequencies previously obtained for Amerindian and Afro-Colombian populations. Amerindian mtDNA haplogroups ranged from 74% to 97%. The lowest frequencies were found in Departments on the Caribbean coast and in the Pacific region, where the frequency of Afro-Colombians is higher, while the highest mtDNA Amerindian haplogroup frequencies were found in Departments that historically have a strong Amerindian heritage. Interestingly, all four mtDNA haplogroups were found in all Departments, in contrast to the complete absence of haplogroup D and high frequencies of haplogroup A in Amerindian populations in the Caribbean region of Colombia. Our results indicate that all four Native American mtDNA haplogroups were widely distributed in Colombia at the time of the Spanish conquest.

MHC Class II haplotypes of Colombian Amerindian tribes.

We analyzed 1041 individuals belonging to 17 Amerindian tribes of Colombia, Chimila, Bari and Tunebo (Chibcha linguistic family), Embera, Waunana (Choco linguistic family), Puinave and Nukak (Maku-Puinave linguistic families), Cubeo, Guanano, Tucano, Desano and Piratapuyo (Tukano linguistic family), Guahibo and Guayabero (Guayabero Linguistic Family), Curripaco and Piapoco (Arawak linguistic family) and Yucpa (Karib linguistic family). for MHC class II haplotypes (HLA-DRB1, DQA1, DQB1). Approximately 90% of the MHC class II haplotypes found among these tribes are haplotypes frequently encountered in other Amerindian tribes. Nonetheless, striking differences were observed among Chibcha and non-Chibcha speaking tribes. The DRB1*04:04, DRB1*04:11, DRB1*09:01 carrying haplotypes were frequently found among non-Chibcha speaking tribes, while the DRB1*04:07 haplotype showed significant frequencies among Chibcha speaking tribes, and only marginal frequencies among non-Chibcha speaking tribes. Our results suggest that the differences in MHC class II haplotype frequency found among Chibcha and non-Chibcha speaking tribes could be due to genetic differentiation in Mesoamerica of the ancestral Amerindian population into Chibcha and non-Chibcha speaking populations before they entered into South America.

Genetic differences between Chibcha and Non-Chibcha speaking tribes based on mitochondrial DNA (mtDNA) haplogroups from 21 Amerindian tribes from Colombia.

We analyzed the frequency of four mitochondrial DNA haplogroups in 424 individuals from 21 Colombian Amerindian tribes. Our results showed a high degree of mtDNA diversity and genetic heterogeneity. Frequencies of mtDNA haplogroups A and C were high in the majority of populations studied. The distribution of these four mtDNA haplogroups from Amerindian populations was different in the northern region of the country compared to those in the south. Haplogroup A was more frequently found among Amerindian tribes in northern Colombia, while haplogroup D was more frequent among tribes in the south. Haplogroups A, C and D have clinal tendencies in Colombia and South America in general. Populations belonging to the Chibcha linguistic family of Colombia and other countries nearby showed a strong genetic differentiation from the other populations tested, thus corroborating previous findings. Genetically, the Ingano, Paez and Guambiano populations are more closely related to other groups of south eastern Colombia, as also inferred from other genetic markers and from archeological data. Strong evidence for a correspondence between geographical and linguistic classification was found, and this is consistent with evidence that gene flow and the exchange of customs and knowledge and language elements between groups is facilitated by close proximity.

Pharmacogenetics of ABCB1, CDA, DCK, GSTT1, GSTM1 and outcomes in a cohort of pediatric acute myeloid leukemia patients from Colombia.

BACKGROUND AND AIM: Different studies have shown pharmacogenetic variants related to drug toxicity in acute myeloid leukemia (AML) patients. Our aim was to identify the association between ABCB1, CDA, DCK, GSTT1, and GSTM1 variants with clinical outcomes and toxicity in pediatric patients with AML. METHODS: Fifty-one confirmed de novo AML pediatric patients were included. A SNaPshot™ assay and conventional PCR were used to evaluate ABCB1, CDA, DCK, GSTT1, and GSTM1 variants. Clinical outcomes and toxicity associations were evaluated using odds ratios and Chi-square analysis. RESULTS: Patients carrying ABCB1 (1236C > T, rs1128503) GG genotype in had a 6.8 OR (CI 95% 1.08-42.73, p = .044) for cardiotoxicity as compared to patients carrying either AA or GA genotypes 0.14 OR (CI 95% 0.023-0.92, p = .044). For ABCB1 (1236G > A rs1128503/2677C > A/T rs2032582/3435G > A rs1045642) AA/AA/AA combined genotypes had a strong association with death after HSTC OR 13.73 (CI 95% 1.94-97.17, p = .009). Combined genotypes GG/CC/GG with CDA (79A > C, rs2072671) CA genotype or CDA (-451G > A, rs532545) CT genotype, had a 4.11 OR (CI 95% 2.32-725, p = .007) and 3.8 OR (CI 95% 2.23-6.47, p = .027) with MRD >0.1% after first chemotherapy cycle, respectively. CONCLUSION: Our results highlight the importance of pharmacogenetic analysis in pediatric AML, particularly in populations with a high degree of admixture, and might be useful as a future tool for patient stratification for treatment.

Genomic alterations in a cohort of pediatric acute myeloid leukemia patients at two cancer centers in Colombia.

Few studies identifying genomic aspects in pediatric acute myeloid leukemia patients in Latin American countries have been reported. The aim of this study was to identify genomic alterations, clinical characteristics and outcomes in a cohort of pediatric AML patients. This descriptive observational cohort study included patients with confirmed de novo acute myeloid leukemia up to 18 years of age. Cytogenetics and conventional FISH analysis, next-generation sequencing and PCR testing were performed. The correlation of genomic data with treatment response and outcomes were analyzed. Of the 51 patients analyzed, 67.4% had a cytogenetic abnormality and 74.5% had a genetic variant. FLT3 variants (ITD or TKD D835) were found in 27.4%, followed by NRAS (21.6%), KRAS (13.7%) and WT1 and KIT (11.8%). Patients were stratified by risk (66.6% high-risk) after the end of induction. FLT3-ITD was associated with relapse (OR 11.25; CI 1.89-66.72, p 0.006) and NRAS with death during induction (OR 16.71; CI 1.51-184.59, p 0.022). Our study highlights the importance of rapid incorporation of genetic testing in pediatric AML in Colombia, as it directly affects treatment decisions and outcomes. Incorporation of targeted therapies with conventional chemotherapy is an increasingly urgent need in pediatric patients.

Genetic variants in Colombian patients with inherited cardiac conditions.

BACKGROUND: Clinical and molecular diagnosis of inherited cardiac conditions is key to find at-risk subjects and avoid preventable deaths. This study aimed to identify genetic variants in a sample of Colombian patients diagnosed with inherited cardiac conditions. METHODS: Next-generation sequencing (Illumina platform) using a 231 gene panel was performed in blood samples of 25 unrelated patients with age disease onset between 9 and 55 years. RESULTS: Genetic testing yield was 52%. Two novel likely pathogenic/ pathogenic variants were found: a DSP nonsense variant in a patient with arrhythmogenic cardiomyopathy and a KCNE1 frameshift variant in two patients with long QT syndrome. Younger individuals (<18 years) had the highest genetic testing yield (66.6%) compared to 50% and 20% in young adults and patients over 40 years, respectively. All subjects affected with long QT syndrome with a severe event while exercising had a positive genetic test. They also had four times more loss of consciousness events and, resuscitated sudden cardiac arrest was more representative. CONCLUSION: This study is the first one undertaken in Colombia to evaluate inherited cardiac conditions. It highlights the need to perform mutational analysis to provide adequate genetic counseling and to be able to identify patients at risk of severe events.

Philadelphia-like acute lymphoblastic leukemia: Characterization in a pediatric cohort in a referral center in Colombia.

BACKGROUND: Philadelphia-like (Ph-like) acute lymphoblastic leukemia (ALL) is a subtype of pediatric leukemia with high risk factors and poor outcome. There are few reports of its prevalence in Latin America. AIM: This study evaluated the frequency and clinical and biological characteristics of Ph-like ALL in a pediatric cancer center in Colombia. METHODS: The Ph-like genetic profile was analyzed by a low-density array (LDA). Samples from patients with Ph-like ALL were analyzed by fluorescent in situ hybridization for cytokine receptor like factor 2 (CRLF2) and ABL proto-oncogene 1, non-receptor tyrosine kinase (ABL1) rearrangements. Copy number variations were assessed by multiplex ligation probe amplification. RESULTS: Data from 121 patients were analyzed. Fifteen patients (12.4%) had Ph-like ALL, and these patients had significantly higher leukocyte counts at diagnosis and higher levels of minimal residual disease on days 15 and 33 of induction than patients without the Ph-like subtype. There were no significant differences in sex, age, or response to prednisone at day 8 between the two groups. CRLF2 rearrangements were identified in eight patients, and ABL1 rearrangements were identified in two patients. Other genetic alterations alone or in combination were identified in 77% of patients, including deletions in cyclin dependent kinase inhibitor 2 A/B (46.2%), IKAROS family zinc finger 1 (38.3%), and paired box 5 (30.8%). CONCLUSIONS: Ph-like ALL had a 12.4% prevalence in our cohort of patients with pediatric ALL. The identification of this group of patients has importance for risk stratification and future targeted therapy.

Susceptibility to thiopurine toxicity by TPMT and NUDT15 variants in Colombian children with acute lymphoblastic leukemia.

Objective: This study aimed to correlate the genetic profile of the NUDT15 and TPMT genes with the side effects of the treatment of pediatric patients with acute lymphoid leukemia who were undergoing maintenance therapy at a tertiary care hospital in 2017. Methods: This was an analytical, longitudinal, observational study in which the genotypes of the genes of interest were determined by PCR allelic discrimination with TaqMan® probes in patients receiving chemotherapy during the maintenance phase in the Pediatric Hematology and Oncology Unit in 2017. Sociodemographic and clinical data corresponding to the first six months of their maintenance chemotherapy were collected, and the correlation between the genotypes obtained and the development of side effects during the maintenance phase of chemotherapy in these patients was evaluated. Results: Seventy pediatric patients were included in the study. Genetic analyses were carried out of these for NUDT15 and TPMT (rs1800462 and rs1800460) on 68 patients, while for the rs1142345 polymorphism, typing was achieved in 42 patients. 4/68 patients were heterozygous for NUDT15, and the same number of patients were heterozygous for rs1800462 and rs1142345, while for rs1800460, 6 heterozygous patients were identified. No statistically significant association was identified between the genetic variants and the outcomes of interest. Conclusion: Studies with a larger population size are needed and the evaluation of other genetic variants that may influence the development of side effects during maintenance chemotherapy.

Objetivo: la finalidad de este estudio fue evaluar las asociaciones entre los perfiles de los genes NUDT15 y TPMT con los efectos adversos del tratamiento de mantenimiento en pacientes pediátricos con Leucemia Linfoblástica Aguda atendidos en un hospital de referencia durante el 2017. Métodos: Este fue un estudio observacional analítico, de corte longitudinal en el que los genotipos de los genes de interés fueron determinados mediante PCR de discriminación alélica con sondas TaqMan® en pacientes que estaban recibiendo quimioterapia de mantenimiento en la Unidad de Oncohematología Pediátrica durante el 2017. Los datos clínicos y sociodemográficos correspondientes a los primeros 6 meses de sus tratamientos de mantenimiento fueron colectados, y se evaluó la correlación entre los genotipos identificados y el desarrollo de efectos secundarios en estos pacientes. Resultados: setenta pacientes fueron incluidos en el estudio, de estos, los análisis genéticos para NUDT15 y TPMT (rs1800462 and rs1800460) fueron realizados en 68 pacientes, en tanto que para el polimorfismo rs1142345 se logró la tipificación en 42 pacientes. 4/68 pacientes fueron heterocigotos para NUDT15 y el mismo número de pacientes fueron heterocigotos para rs1800462 and rs1142345, mientras que para rs1800460, 6 pacientes heterocigotos fueron identificados. No se identificaron asociaciones estadísticamente significantes entre las variants genéticas y los resultados clínicos de interés. Conclusiones: Estos hallazgos resaltan la importancia de realizar estudios de este tipo con un mayor número de sujetos de estudio, así como plantean la necesidad de evaluar otras variantes genéticas que podrían tener algún impacto en el desarrollo de efectos secundarios durante la quimioterapia de mantenimiento.

[Brain-lung-thyroid syndrome in a newborn with deletion 14q12-q21.1]. / Síndrome cerebro-pulmón-tiroides en un recién nacido con deleción 14q12-q21.1.

INTRODUCTION: In newborns with respiratory failure and interstitial lung disease, it should be approached as chILD (Childhood Interstitial Lung Disease) syndrome to rule out alterations in surfactant metabolism and brain-lung-thyroid syndrome caused by pathogenic variants in the NKX2-1 gene. OBJECTIVE: To pre sent a newborn with chILD syndrome and a large deletion in chromosome 14q12-q21.1. CLINICAL CASE: Newborn patient with respiratory distress since birth, chILD syndrome, and hypothyroidism, in which brain-lung-thyroid syndrome was suspected. He also presented seizures, minor and ma jor abnormalities on physical examination. Microarray analysis revealed a 14.7 Mb deletion in the chromosome 14q12-q21.1, which includes the NKX2-1 gene. CONCLUSION: The brain-lung-thyroid syndrome should be considered in newborns with respiratory distress syndrome and diffuse lung disease (chILD syndrome), especially if they present hypotonia, choreoathetosis, or hypothyroidism. Diagnosis confirmation requires genetic analysis, even more, when there are other abnormalities not explained by the suspected syndrome.

Absence of Lamin A/C gene mutations in four Wiedemann-Rautenstrauch syndrome patients.

The Wiedemann-Rautenstrauch syndrome (WRS, OMIM: 264090) characterizes a premature aging syndrome in which several features of aging are apparent at birth. We did not find mutations in Lamin A/C (LMNA) gene in four WRS patients, and in particular, we did not find the G608G mutation (GGC > GGT transition) which is associated with most cases with Hutchinson-Gilford progeria (OMIM 176670). These findings suggest that WRS represents a distinct progeroid entity that may be caused by recessive mutations of a different gene.

Parental origin, nondisjunction, and recombination of the extra chromosome 21 in Down syndrome: a study in a sample of the Colombian population.

INTRODUCTION: Free trisomy 21 is responsible for 95% of Down syndrome cases. Advanced maternal age and susceptible recombination patterns are recognized risk factors associated to Down syndrome. Maternal origin of trisomy occurs in approximately 90% of cases; paternal and mitotic origin share the remaining 10%. However, the recombination events that serve as a risk factors for trisomy 21 have not been carefully characterized. OBJECTIVE: To analyze and validate observations in a sample of Colombian trysonomy 21 cases. MATERIALS AND METHODS: Twenty-two Colombian families were selected, each with one affected Down syndrome (free trisomy 21) child. Microsatellite polymorphisms were used as DNA markers to determine the parental/stage origin of non-disjunction and recombination events. Non-parametric tests were used to compare our results with those reported. Multiple correspondence analysis was used to outline different groups and their associations. RESULTS: Distribution of trisomy 21 was 90.9% maternal, 4.5% paternal and 4.5% from mitotic origin, similar to distributions reported previously. However, we found differences in the frequency of maternal meiotic stage errors between the present study (46.1% meiosis I and 53.9% meiosis II) compared to those reported previously (70% meiosis I and 30% meiosis II). Multiple correspondence analyses showed association of either local recombination events or absence of recombination with specific non-disjunction stages. CONCLUSIONS: Recombination patterns found in this study support the hypothesis that susceptible chiasmate configurations are associated to maternal meiosis I and meiosis II errors. Non-disjunction frequencies between maternal meiotic stages need to be clarified in our population.

Analysis of functional polymorphisms in three synaptic plasticity-related genes (BDNF, COMT AND UCHL1) in Alzheimer's disease in Colombia.

In recent years, it has been proposed that synaptic dysfunction may be an important etiological factor for Alzheimer's disease (AD). This hypothesis has important implications for the analysis of AD genetic risk in case-control studies. In the present work, we analyzed common functional polymorphisms in three synaptic plasticity-related genes (brain-derived neurotrophic factor, BDNF Val66Met; catechol-O-methyl transferase, COMT Val158; ubiquitin carboxyl-terminal hydroxylase, UCHL1 S18Y) in a sample of 102 AD cases and 168 age and sex matched controls living in Bogotá, Colombia. There was not association between UCHL1 polymorphism and AD in our sample. We have found an initial association with BDNF polymorphism in familial cases and with COMT polymorphism in male and sporadic patients. These initial associations were lost after Bonferroni correction for multiple testing. Unadjusted results may be compatible with the expected functional effect of variations in these genes on pathological memory and cognitive dysfunction, as has been implicated in animal and cell models and also from neuropsychological analysis of normal subjects carriers of the AD associated genotypes. An exploration of functional variants in these and in other synaptic plasticity-related genes (a synaptogenomics approach) in independent larger samples will be important to discover new genes associated with AD.

Analysis of common polymorphisms in angiotensin-converting enzyme and apolipoprotein e genes and human longevity in Colombia.

BACKGROUND: Genetic analysis of human longevity may be useful for the understanding of molecular mechanisms implicated in age-related diseases. The molecular genetics of human longevity is largely unexplored in Latin American populations and other developing countries. METHODS: To explore the possibility of an association of common polymorphisms in two candidate genes and longevity in Colombia, we analyzed two polymorphisms in apolipoprotein E (APOE) and angiotensin-converting enzyme (ACE) genes in a sample of 538 Colombian subjects (18-106 years), using previously validated PCR-based methodologies. RESULTS: We found a significant decrease in ACE DD genotype (24 vs. 16%) between young and old subject groups (mean age: 45 vs. 77 years) (p = 0.03). The ACE DD genotype and D allele decrease was significant only in women. There were no differences for APOE polymorphism between young and old subjects. CONCLUSIONS: Our results are compatible with the expected age-related decrease of ACE DD genotype. Future studies examining functional single nucleotide polymorphisms (SNPs) in the ACE gene and its correlation with serum ACE activity in the older subjects and their younger relatives in this sample are warranted.

Results of the 2003-2004 GEP-ISFG collaborative study on mitochondrial DNA: focus on the mtDNA profile of a mixed semen-saliva stain.

We report here a review of the seventh mitochondrial DNA (mtDNA) exercise undertaken by the Spanish and Portuguese working group (GEP) of the International Society for Forensic Genetics (ISFG) corresponding to the period 2003-2004. Five reference bloodstains from five donors (M1-M5), a mixed stain of saliva and semen (M6), and a hair sample (M7) were submitted to each participating laboratory for nuclear DNA (nDNA; autosomal STR and Y-STR) and mtDNA analysis. Laboratories were asked to investigate the contributors of samples M6 and M7 among the reference donors (M1-M5). A total of 34 laboratories reported total or partial mtDNA sequence data from both, the reference bloodstains (M1-M5) and the hair sample (M7) concluding a match between mtDNA profiles of M5 and M7. Autosomal STR and Y-STR profiling was the preferred strategy to investigate the contributors of the semen/saliva mixture (M6). Nuclear DNA profiles were consistent with a mixture of saliva from the donor (female) of M4 and semen from donor M5, being the semen (XY) profile the dominant component of the mixture. Strikingly, and in contradiction to the nuclear DNA analysis, mtDNA sequencing results yield a more simple result: only the saliva contribution (M4) was detected, either after preferential lysis or after complete DNA digestion. Some labs provided with several explanations for this finding and carried out additional experiments to explain this apparent contradictory result. The results pointed to the existence of different relative amounts of nuclear and mtDNAs in saliva and semen. We conclude that this circumstance could strongly influence the interpretation of the mtDNA evidence in unbalanced mixtures and in consequence lead to false exclusions. During the GEP-ISFG annual conference a validation study was planned to progress in the interpretation of mtDNA from different mixtures.