Local allele frequencies of the 5-HTTLPR serotonin transporter promoter polymorphism

The Serotonin Transporter protein (5-Hydroxytryptamine transporter; 5-HTT) is an important reuptake receptor of serotonin from the synaptic cleft. The protein is encoded by the SLC6A4 gene. A size polymorphism, the 5-HTT Linked Polymorphic Region (5-HTTLPR; SLC6A4, 44-BP INS/DEL), exists within the promoter of this gene. The presence of this polymorphism has been associated with an increased susceptibility for a variety of neurological conditions including Parkinson disease, chronic pain, anxiety and depression related phenotypes. This 5' regulatory promoter polymorphism consists of a 44–base pair insertion resulting in a long or short allele. The short allele is linked to a pronounced reduction in transcriptional efficiency producing lower numbers of transporter protein and a reduced rate of serotonin reuptake. Allele frequencies for this polymorphism show substantial variation in different populations. The frequency of the 5-HTTLPR in the population of Malta was determined in 608 cord blood DNA samples. Allele size difference of the 5-HTTLPR was detected using Polymerase Chain Reaction (PCR) and agarose gel electrophoresis. In total, 288 samples were found to be heterozygous (L/S) carrying 1 copy of the short allele and 1 copy of the long allele, while 129 samples were homozygous for the short allele (S/S) and 189 samples were homozygous for the long allele (L/L). Unexpectedly, 2 samples were found to carry a copy of the extra-long allele (XL) which is reportedly only found in African and Asian populations. Allele frequencies for L, S and XL alleles were 54.86%, 44.98% and 0.16% respectively. These local frequencies are similar to those of other European populations with the exception of the occurrence of the XL allele. These findings highlight the changing dynamics of population gene pools, the importance of selecting suitably matched controls for case-control studies and the importance of ethnicity information in the design, execution and interpretation of genetic diagnostic tests.peer-reviewe

Comparative frequency of Coagulation Factor II and Coagulation Factor V Alleles among new-born and senior citizens

Resistance to activated protein C is one of the most common inherited disorders associated with hereditary thrombophilia. A missense mutation in the gene coding for coagulation factor V (CF V Leiden) and which renders this procoagulant factor resistant to inactivation by activated protein C results in an inherited risk for venous thrombosis. Recently, another mutation has been identified in the prothrombin gene (CF II G20210A) which was also associated with increased risk for venous thrombosis. In this study, we sought to establish the frequency of the two alleles in a random sample of Maltese newborn and compare these with the frequencies of the same alleles among senior citizens and patients with clinical thrombophilia. The control population of 554 newborn samples processed for the same point mutations gave 13 (2.3%) who were CF V Leiden heterozygotes and 7 (2.7%) who were CF II G20210A heterozygotes. Neither homozygotes nor trans-heterozygotes (i.e. CF V Leden and CF II2 0210A heterozygotes) were observed. The 348 senior citizens gave 9 (2.6%) CF V Leiden heterozygotes and 8 (2.4%) CF II G20210A heterozygotes. Neither homozygotes nor trans-heterozygotes (i.e. CF V Leden and CF II20210A heterozygotes) were observed. The 328 patients referred to the Laboratory of Molecular Genetics, University of Malta, with clinical thrombosis gave 23 (7.01%) CF V Leiden heterozygotes and 24 (7.31%) CF II G20210A heterozygous. One patient was found to be trans-heterozygous for the two mutations. The data suggested that although CF V G1691A and CF II G20210A may increase risk for thrombophilia, they do not impact on the survival of the carriers, but the transheterozygozity may also confer increased risk. The high allele frequency may be best explained by positive natural selection.peer-reviewe

Genetic causes of Parkinson’s disease in the Maltese : a study of selected mutations in LRRK2, MTHFR, QDPR and SPR

The samples and data used in this study were collected as part of the 5th framework (FP5) EU funded Geoparkinson study, project number QLK4‐CT‐ 1999‐01133. The Maltese arm of this group included Prof Christian Scerri, Dr Joseph Borg, Dr Karen Cassar, Ms Wilma Cassar, Ms Ruth Galdies, Dr Norbert Vella, Dr Vicky Mifsud, Dr Josanne Aquilina and Dr Galea Debono.Background: Mutations in Leucine-rich repeat kinase 2 NM_198578 (LRRK2 c.6055G>A (p.G2019S), LRRK2 c.4321C>G (p.R1441G)) and alpha-synuclein NM_000345 (SNCA c.209G>A (p.A53T)) genes causing Parkinson's disease (PD) are common in Mediterranean populations. Variants in the Quinoid Dihydropteridine Reductase NM_000320 (QDPR c.68G>A (p.G23D)), Sepiapterin Reductase NM_003124 (SPR c.596-2A>G) and Methylenetetrahydrofolate Reductase NM_005957 (MTHFR c.677C>T and c.1298A>C) genes are frequent in Malta and potential candidates for PD. Methods: 178 cases and 402 control samples from Malta collected as part of the Geoparkinson project were genotyped for MTHFR polymorphisms, QDPR and SPR mutations. Only PD and parkinsonism cases were tested for SNCA and LRRK2 mutations. Results: LRRK2 c.4321C>G and SNCA c.209G>A were not detected. The LRRK2 c.6055G>A mutation was found in 3.1 % of Maltese PD cases. The QDPR mutation was found in both cases and controls and did not increase risk for PD. The SPR mutation was found in controls only. The odds ratios for MTHFR polymorphisms were not elevated. Conclusions: The LRRK2 c.6055G>A is a cause of PD in the Maltese, whilst QDPR c.68G>A, SPR c.596-2A>G and MTHFR c.677C>T and c.1298A>C are not important determinants of PD.The samples and data used in this study were collected as part of the 5th framework (FP5) EU funded Geoparkinson study, project number QLK4‐CT‐ 1999‐01133. This work was supported by research grants of SBW and RF from the University of Malta. The funders played no other part in the research or its interpretation.peer-reviewe

Multiomics tools for improved atherosclerotic cardiovascular disease management

Multiomics studies offer accurate preventive and therapeutic strategies for atherosclerotic cardiovascular disease (ASCVD) beyond traditional risk factors. By using artificial intelligence (AI) and machine learning (ML) approaches, it is possible to integrate multiple ‘omics and clinical data sets into tools that can be utilized for the development of personalized diagnostic and therapeutic approaches. However, currently multiple challenges in data quality, integration, and privacy still need to be addressed. In this opinion, we emphasize that joined efforts, exemplified by the AtheroNET COST Action, have a pivotal role in overcoming the challenges to advance multiomics approaches in ASCVD research, with the aim to foster more precise and effective patient care

High population frequency of GNRHR p. Q106R in Malta : an evaluation of fertility and hormone profiles in heterozygotes

Context: The gonadotropin-releasing hormone receptor variant GNRHR p.Q106R (rs104893836) in homozygosity, compound heterozygosity, or single heterozygosity is often reported as the causative variant in idiopathic hypogonadotropic hypogonadism (IHH) patients with GnRH deficiency. Genotyping of a Maltese newborn cord-blood collection yielded a minor allele frequency (MAF) 10 times higher (MAF = 0.029; n = 493) than that of the global population (MAF = 0.003). Objective: To determine whether GNRHR p.Q106R in heterozygosity influences profiles of endogenous hormones belonging to the hypothalamic-pituitary axis and the onset of puberty and fertility in adult men (n = 739) and women (n = 239). Design, Setting, and Participants: Analysis of questionnaire data relating to puberty and fertility, genotyping of the GNRHR p.Q106R variant, and hormone profiling of a highly phenotyped Maltese adult cohort from the Maltese Acute Myocardial Infarction Study. Main Outcome and Results: Out of 978 adults, 43 GNRHR p.Q106R heterozygotes (26 men and 17 women) were identified. Hormone levels and fertility for all heterozygotes are within normal parameters except for TSH, which was lower in men 50 years or older. Conclusion: Hormone data and baseline fertility characteristics of GNRHR p.Q106R heterozygotes are comparable to those of homozygous wild-type individuals who have no reproductive problems. The heterozygous genotype alone does not impair the levels of investigated gonadotropins and sex steroid hormones or affect fertility. GNRHR p.Q106R heterozygotes who exhibit IHH characteristics must have at least another variant, probably in a different IHH gene, that drives pathogenicity. We also conclude that GNRHR p.Q106R is likely a founder variant due to its overrepresentation and prevalence in the island population of Malta.peer-reviewe

Catalyzing Transcriptomics Research in Cardiovascular Disease : The CardioRNA COST Action CA17129

Cardiovascular disease (CVD) remains the leading cause of death worldwide and, despite continuous advances, better diagnostic and prognostic tools, as well as therapy, are needed. The human transcriptome, which is the set of all RNA produced in a cell, is much more complex than previously thought and the lack of dialogue between researchers and industrials and consensus on guidelines to generate data make it harder to compare and reproduce results. This European Cooperation in Science and Technology (COST) Action aims to accelerate the understanding of transcriptomics in CVD and further the translation of experimental data into usable applications to improve personalized medicine in this field by creating an interdisciplinary network. It aims to provide opportunities for collaboration between stakeholders from complementary backgrounds, allowing the functions of different RNAs and their interactions to be more rapidly deciphered in the cardiovascular context for translation into the clinic, thus fostering personalized medicine and meeting a current public health challenge. Thus, this Action will advance studies on cardiovascular transcriptomics, generate innovative projects, and consolidate the leadership of European research groups in the field.COST (European Cooperation in Science and Technology) is a funding organization for research and innovation networks (www.cost.eu)

The impact of frequency, pattern, intensity, and type of alcohol consumption, and its combined effect with smoking on inflammation, lipid profile, and the risk of myocardial infarction

Aim: To determine the risk of myocardial infarction (MI) associated with pattern, frequency, and intensity of alcohol consumption, type of alcoholic beverage, and the combined effect of alcohol and smoking on risk of MI, inflammation, and lipid profile. Method: A total of 423 cases with a first MI and 465 controls from the Maltese Acute Myocardial Infarction (MAMI) Study were analysed. Data was collected through an extensive interviewer-led questionnaire, along with measurements of various blood parameters. Medians and the Mann–Whitney test were used to assess effect of different drinking patterns, frequency, intensity, and smoking and drinking combinations on hs-CRP and lipid profile. Odds ratios, adjusted for the conventional risk factors of MI (AdjORs), were calculated as an estimate of the relative risk of MI. Results: Regular alcohol consumption protected against MI [AdjOR 0.6 (95% CI 0.4–0.9)] while daily binge drinking increased risk [AdjOR 5.0 (95% CI 1.6–15.0)] relative to regular drinkers who did not binge drink. Whereas moderate weekly consumption of wine protected against MI, high weekly consumption of beer conveyed a deleterious effect. Alcohol consumption decreased risk of MI independent of smoking status. Frequent alcohol consumption was associated with higher HDL-, non-HDL-, total cholesterol and triglycerides, and lower hs-CRP. Total and HDL-cholesterol increased and BMI decreased with increasing quantity of weekly alcohol consumption relative to the non-regular drinkers. The effect of smoking on lipid profile and hs-CRP was less pronounced in current drinkers than in those who were non-regular drinkers. Conclusion: The protective effect of alcohol consumption was dependent on the pattern, frequency, type, and intensity of alcohol consumed. Alcohol modified the effects of smoking on the lipid profile. Regular drinking attenuated the effect of smoking on hs-CRP and lipid profile

The impact of passive and active smoking on inflammation, lipid profile and the risk of myocardial infarction

Objective: To investigate the effect of passive smoking, active smoking and smoking cessation on inflammation, lipid profile and the risk of myocardial infarction (MI). Methods: A total of 423 cases with a first MI and 465 population controls from the Maltese Acute Myocardial Infarction (MAMI) Study were analysed. Data were collected through an interviewer-led questionnaire, and morning fasting blood samples were obtained. ORs adjusted for the conventional risk factors of MI (aORs) were calculated as an estimate of the relative risk of MI. The influence of smoking on biochemical parameters was determined among controls. Results: Current smokers had a 2.7-fold (95% CI 1.7 to 4.2) and ex-smokers a 1.6-fold (95% CI 1.0 to 2.4) increased risk of MI. Risk increased with increasing pack-years and was accompanied by an increase in high-sensitivity C reactive protein levels and an abnormal lipid profile. Smoking cessation was associated with lower triglyceride levels. Exposure to passive smoking increased the risk of MI (aOR 3.2 (95% CI 1.7 to 6.3)), with the OR being higher for individuals exposed to passive smoking in a home rather than in a public setting (aOR 2.0 (95% CI 0.7 to 5.6) vs aOR 1.2 (95% CI 0.7 to 2.0)). Passive smoke exposure was associated with higher levels of total cholesterol, triglycerides and total cholesterol:high-density lipoprotein cholesterol ratio compared with individuals not exposed to passive smoking. Conclusions: Both active and passive smoking are strong risk factors for MI. This risk increased with increasing pack-years and decreased with smoking cessation. Such effects may be partly mediated through the influence of smoking on inflammation and lipid metabolism

High throughput mRNA profiling highlights associations between myocardial infarction and aberrant expression of inflammatory molecules in blood cells \ud

Studies on the role of inflammation in cardiovascular disease focus on surrogate markers like plasma levels of C-reactive protein or interleukins that are affected by several factors. In this study we employ an approach in which the inflammatory mRNA profile of leucocytes is measured directly in a multigene system. We investigated the mRNA profile for 35 inflammatory markers in blood samples in a case-control study including 524 men with a history of myocardial infarction and 628 control subjects. Compared with controls, patients showed mRNA profiles with increased levels of most inflammatory mRNAs. The 2 most prominent mRNA risk indicators encoded the secreted protein macrophage migration inhibitory factor (crude odds ratio [OR], 3.4 for the highest quartile versus the lowest quartile (95% confidence interval [CI95], 2.3-4.9), and the intracellular regulator proteinase inhibitor 9 (OR, 2.5 for the highest versus the lowest quartile (CI95, 1.8-3.5), both showing an increase in odds ratio with increasing quartiles. Leucocytes in the blood of patients with myocardial infarction are more active in transcription of inflammatory genes, as evidenced by mRNA profiling. These data support the hypothesis that an inflammatory response involving leucocytes plays a role in the pathogenesis of myocardial infarctio

The impact of passive and active smoking on inflammation, lipid profile and the risk of myocardial infarction

Objective To investigate the effect of passive smoking, active smoking and smoking cessation on inflammation, lipid profile and the risk of myocardial infarction (MI)Methods A total of 423 cases with a first MI and 465 population controls from the Maltese Acute Myocardial Infarction (MAMI) Study were analysed. Data were collected through an interviewer-led questionnaire, and morning fasting blood samples were obtained. ORs adjusted for the conventional risk factors of MI (aORs) were calculated as an estimate of the relative risk of MI. The influence of smoking on biochemical parameters was determined among controls.Results Current smokers had a 2.7-fold (95%CI 1.7 to 4.2) and ex-smokers a 1.6-fold (95%CI 1.0 to 2.4) increased risk of MI. Risk increased with increasing pack-years and was accompanied by an increase in highsensitivity C reactive protein levels and an abnormal lipid profile. Smoking cessation was associated with lower triglyceride levels. Exposure to passive smoking increased the risk of MI (aOR 3.2 (95% CI 1.7 to 6.3)), with the OR being higher for individuals exposed to passive smoking in a home rather than in a public setting (aOR 2.0 (95% CI 0.7 to 5.6) vs aOR 1.2 (95% CI 0.7 to 2.0)). Passive smoke exposure was associated with higher levels of total cholesterol, triglycerides and total cholesterol:high-density lipoprotein cholesterol ratio compared with individuals not exposed to passive smoking.Conclusions Both active and passive smoking are strong risk factors for MI. This risk increased with increasing pack-years and decreased with smoking cessation. Such effects may be partly mediated through the influence of smoking on inflammation and lipid metabolism.peer-reviewe