Ainda são escassos estudos que avaliem biomarcadores para diferenciação de transtorno depressivo maior (TDM) e transtorno bipolar (TB), principalmente relativo à etiologia desses transtornos e sua relação com os receptores glicocorticoides (GR) e, principalmente, com os receptores mineralocorticoides (MR). Objetivo: Encontrar biomarcadores genéticos e/ou hormonais e observar sua associação entre si e/ou a fatores externos (estresse precoce - EP) para compreender melhor sua fisiopatogenia e auxiliar no diagnóstico diferencial entre TDM e TB. Material e Métodos: Participaram deste estudo N=273 sujeitos, sendo n=113 controles, n=78 unipolares e n=82 bipolares. A triagem diagnóstica de todos os sujeitos foi realizada por meio do MINI PLUS, checagem de história de trauma na infância pela CTQ, avaliação de sintomas depressivos pela GRID-HAM-D21, e demais comorbidades pela BAI, BHS e BSI. Na busca de biomarcador genético, observou-se as frequências genotípicas e alélicas de 3 polimorfismos de receptor de glicocorticoide (GR) (N363S, R22/23K e BclI) e de 2 polimorfismos de MR (MI180V e -2G/C) após realizada a discriminação alélica por reação em cadeia da polimerase quantitativa (qPCR). Foram avaliados de forma intragrupo as variáveis genéticas e endócrinas (e combinadas) e o efeito do EP sobre tais variáveis. Também, as variáveis polimorfismos, níveis hormonais e exposição a EP foram comparadas entre grupos para avaliar se havia diferença de prevalência, de perfil endócrino, ou se havia suscetibilidade maior por parte dos unipolares ou bipolares para alteração dos níveis hormonais e/ou intensidade do quadro depressivo frente a EP ou a determinado genótipo. Resultados: Todos os sujeitos unipolares e bipolares mostraram piora de seus sintomas depressivos frente a EP e seus subtipos, sendo eles unipolares ou bipolares. Como biomarcador hormonal, comparando-se controles x unipolares x bipolares, ou apenas unipolares x\' bipolares, foi possível observar que os níveis de cortisol e os níveis de aldosterona apresentaram-se os altos em unipolares e os baixos mais em bipolares, quando estes pacientes estavam com depressão grave ou gravíssima. Também, bipolares expostos a EP global, abuso físico e emocional mostraram níveis mais baixos de aldosterona que bipolares que não foram expostos. Frente a exposição a esses EP global e abuso físico, os bipolares tenderam a se mostrar mais suscetíveis que os unipolares a alteração dos níveis de aldosterona. Para biomarcador genético, frequência de genótipos ou alelos não diferenciaram unipolares de bipolares. Entretanto, houve maior prevalência do genótipo heterozigoto AG de GR N363S em pacientes depressivos uni e bipolares quando comparados com controles. Combinando-se os biomarcadores genéticos e hormonais, unipolares apresentaram níveis mais baixos de cortisol e de aldosterona quando carregavam genótipo variante GG de MR -2G/C, enquanto bipolares mostraram tendência a redução de cortisol quando carregavam o alelo variante G de MR MI180V. Quando comparados os genótipos por si só, intragrupo, novamente o polimorfismo MR -2G/C mostra influência sobre o fenótipo unipolar. Em unipolares, presença do alelo variante G de MR -2G/C piora significativamente o quadro depressivo, mas o alelo variante G de MI180V mostrou-se protetor frente a EP. Tanto os unipolares frente aos outros 4 polimorfismos, quanto os bipolares frente a todos os polimorfismos estudados, apresentaram piora significativa de seu quadro depressivo se expostos a EP. Bipolares mostraram uma tendência a ser mais suscetíveis que unipolares a alterações endócrinas (aldosterona) quando expostos a EP global e abuso físico. Conclusão: Tendo em vista os vários achados significativos a cerca dos polimorfismos de MR, tanto para unipolar quanto para bipolar, sua influência sobre os níveis de aldosterona e cortisol basais, reforça-se a importância do papel dos receptores MR dentro da etiologia dos transtornos depressivos unipolares e bipolares, e a forma diferente de funcionamento do MR para a distinção entre TDM e TB / There are still few studies assessing biomarkers for differentiation of major depressive disorder (MDD) and bipolar disorder (TB), mainly related to the etiology of these disorders and its relationship with glucocorticoid receptors (GR) and, manily, with mineralocorticoid receptors (MR). Aim: Finding genetic and / or hormonal biomarkers and observing their association to each other and / or external factors (early-life stress - ELS) for better comprehend their pathophysiology and, then, assisting in differential diagnosis between MDD and TB. Material and Methods: A total of N = 273 subjects composed the study sample, being n = 113 control, n = 78 unipolar, and n = 82 bipolar subjects. The diagnostic screening of all subjects was performed applying MINI PLUS, for history of ELS, CTQ; assessment of depressive symptoms, GRID-HAM-D21; and assessment of other comorbidities, BAI, BHS, and BSI. Researching for genetic biomarker, genotypic and allelic frequencies of 3 GR polymorphisms (N363S, R22 / 23K and BclI) and 2 MR polymorphisms (MI180V and -2G/C) were evaluated after allelic discrimination by quantitative polymerase chain reaction (qPCR). Genetic and endocrine variables (and their combination), and the effect of ELS over these variables were assessed intragrups. Also, polymorphisms, hormonal levels and history to ELS were compared between groups to assess whether there was difference in prevalence, endocrine profile, or whether there was greater susceptibility on the part of unipolar or bipolar for alteration of hormonal levels and / or severity of depressive symptoms considering history of ELS and/or a specific genotype. Results: All unipolar and bipolar subjects showed worsening of their depressive symptoms in the presence of ELS and its subtypes. As hormonal biomarker, comparing unipolar x bipolar x control subjects, or comparing unipolar x bipolar, cortisol and aldosterone levels were higher in unipolar subjects, and lower in bipolar subjects, when these patients presented severe or very severe depressive symptoms. Also, bipolar subjects\' exposed to global ELS, physical and emotional abuse showed lower basal levels of aldosterone than did bipolar who were not exposed to ELS. Concerning global ELS and physical abuse, bipolar tended to be more susceptible than unipolar for aldosterone levels to change. For genetic biomarker, frequency of genotypes or alleles did not distinguished unipolar from bipolar sample. However, there was a higher prevalence of GR N363S heterozygous genotype (AG) in unipolar and bipolar depressive patients when compared to controls. Combining the genetic and hormonal biomarkers, unipolar had lower levels of cortisol and aldosterone when carrying GG variant genotype of MR-2G / C, while bipolar showed tendency to reduce cortisol when carrying the variant G allele of MR MI180V. When comparing the genotypes (intragroup), again, MR-2G/C polymorphism shows influence on the unipolar phenotype. In unipolar, the presence of the variant G allele of MR-2G / C significantly worsens the depressive condition, unlike variant G allele of MI180V has shown to be protective against ELS. Both the unipolar compared to the other 4 polymorphisms, and the bipolar ones against all polymorphisms studied, presented a significant worsening of their depressive condition if exposed to ELS. Bipolar tend to be more susceptible than unipolar to endocrine changes (aldosterone) when exposed to global ELS and physical abuse. Conclusion: Considering the several significant findings regarding MR polymorphisms, for both unipolar and bipolar subjects, and their influence on basal aldosterone and cortisol levels, we highlight importance of the role of MR receptors within the etiology of depressive unipolar and bipolar disorders, and different way of MR functioning in each disorder for assisting the distinction between MDD and TB

<p>Most human traits and common diseases have a complex genetic makeup involving more than one gene. The work presented in this thesis investigates standing body height and the common disease type 2 diabetes mellitus (T2DM). In study I we analyzed two single nucleotide polymorphisms (SNPs) in the TCF7L2 gene that had been shown to be associated with T2DM. Analysis was performed in the ULSAM population cohort of ~1500 males. We were able to replicate the association to type 2 diabetes and in addition to that we made a novel find, showing association between the risk alleles and increased proinsulin levels. In study II we analyzed four genes identified to be associated with T2DM in a genome-wide association study. We analyzed SNPs in these genes in the ULSAM population cohort and found an association between SNPs in the HHEX gene and insulin responses and insulin levels. </p><p>The aim of studies III-V was to identify genes affecting normal variation in standing body height. Using a candidate gene approach in study III, 17 genes were screened in the ULSAM population cohort using SNPs. A suggestive association of the ESR1 gene with height was found and confirmed as significant in males from the PIVUS population cohort. In study IV, as a part of the GenomEUtwin project, we performed genetic fine mapping of a linked locus for body height on the X-chromosome. By analyzing 1377 SNPs in 780 Finnish twins, we mapped a region spanning 65kb of this locus with linkage to body height in males. This region contains the GPC3 and PHF6 genes that have known connections to syndromes were standing body height is affected. In study V significant linkage and association to standing body height in males was found for the COL1A11 gene, using population cohorts from Finland and Iceland. </p>

Nucleic acid technology has assumed an essential role invarious areas ofin vitrodiagnostics ranging from infectious diseasediagnosis to human genetics. An important requirement of suchmolecular methods is that they achieve high sensitivity andspecificity with a fast turnaround time in a cost-effectivemanner. To this end, in this thesis we have focused on thedevelopment of sensitive nucleic acid strategies thatfacilitate automation and high-throughput analysis. The success of nucleic acid diagnostics in the clinicalsetting depends heavily on the method used for purification ofthe nucleic acid target from biological samples. Here we havefocused on developing strategies for hybridisation capture ofsuch templates. Using biosensor technology we observed that thehybridisation efficiency could be improved using contiguousoligonucleotide probes which acted co-operatively. Byimmobilising one of the probes and annealing the second probein solution, we achieved a marked increase in target capturedue to a base stacking effect between nicked oligonucleotidesand/or due to the opening up of secondary structure. Suchco-operatively interacting modular probes were then combinedwith bio-magnetic bead technology to develop a capture systemfor the extraction of hepatitis C RNA from serum. Viral capturewith such co-operatively interacting probes extracted 2-foldmore target as capture with only a single probe achieving asimilar sensitivity to the conventional extraction protocol. Ananalogous strategy was designed to enrich for sequencingproducts prior to gel electrophoresis removing sequencingreagents and template DNA which interfere with the separationand detection of sequencing ladders, especially in the case ofcapillary gel electrophoresis. This protocol facilitates highthroughput clean-up of cycle sequencing reactions resulting inaccurate sequence data at a low cost, which is a pre-requisitefor large-scale genome sequencing products. Currently, a large effort is directed towards differentialsequencing to identify mutations or polymorphisms both in theclinical laboratory and in medical genetics. Inexpensive, highthroughput methods are therefore required to rapidly screen atarget nucleic acid for sequence based changes. In the clinicalsetting, sequence analysis of human immunodeficiency virus(HIV-1) is used to determine the presence of drug resistancemutations. Here we describe a bioluminometric pyrosequencingapproach to rapidly screen for the presence of drug resistancemutations in the protease gene of HIV-1. This sequencingstrategy can analyse the protease gene of HIV-1 from eightpatients in less than an hour and such non-gel based approachesshould be useful in the future in a clinical setting for rapid,robust mutation detection. Microarray technology facilitates large-scalemutation/polymorphism detection and here we developed amicroarray based single nucleotide polymorphism (SNP)genotyping strategy based on apyrase mediated allele specificextension (AMASE). AMASE exploits the fact that mismatchedprimers exhibit slower reaction kinetics than perfectly matchedprimers by including a nucleotide degrading enzyme (apyrase)which results in degradation of the nucleotides before themismatched primer can be extended. We have successfully typed200 genotypes (14% were incorrect without apyrase) by AMASEwhich cluster into three distinct groups representing the threepossible genotypes. In the future, AMASE on DNA microarraysshould facilitate association studies where an accuracy&gt;99%is required. <b>Keywords:</b>nucleic acid capture, modular probes,biosensor, bio-magnetic separation, hepatitis C, sequencing,pyrosequencing, mutation detection, HIV-1, drug resistance,SNP, allele-specific extension, apyrase, genotyping.

Most human traits and common diseases have a complex genetic makeup involving more than one gene. The work presented in this thesis investigates standing body height and the common disease type 2 diabetes mellitus (T2DM). In study I we analyzed two single nucleotide polymorphisms (SNPs) in the TCF7L2 gene that had been shown to be associated with T2DM. Analysis was performed in the ULSAM population cohort of ~1500 males. We were able to replicate the association to type 2 diabetes and in addition to that we made a novel find, showing association between the risk alleles and increased proinsulin levels. In study II we analyzed four genes identified to be associated with T2DM in a genome-wide association study. We analyzed SNPs in these genes in the ULSAM population cohort and found an association between SNPs in the HHEX gene and insulin responses and insulin levels. The aim of studies III-V was to identify genes affecting normal variation in standing body height. Using a candidate gene approach in study III, 17 genes were screened in the ULSAM population cohort using SNPs. A suggestive association of the ESR1 gene with height was found and confirmed as significant in males from the PIVUS population cohort. In study IV, as a part of the GenomEUtwin project, we performed genetic fine mapping of a linked locus for body height on the X-chromosome. By analyzing 1377 SNPs in 780 Finnish twins, we mapped a region spanning 65kb of this locus with linkage to body height in males. This region contains the GPC3 and PHF6 genes that have known connections to syndromes were standing body height is affected. In study V significant linkage and association to standing body height in males was found for the COL1A11 gene, using population cohorts from Finland and Iceland.

Developments within the field of genetic analysis have during the last decade become enormous. Advances in DNA sequencing technology have increased throughput from a thousand bases to over a billion bases in a day and decreased the cost thousandfold per base. Nevertheless, to sequence complex genomes like the human is still very expensive and efforts to attain even higher throughputs for less money are undertaken by researchers and companies. Genotyping systems for single nucleotide polymorphism (SNP) analysis with whole genome coverage have also been developed, with low cost per SNP. There is, however, a need for genotyping assays that are more cost efficient per sample with considerably higher accuracy. This thesis is focusing on a technology, based on competitive allele-specific extension and microarray detection, for genetic analysis. To increase specificity in allele-specific extension (ASE), a nucleotide degrading enzyme, apyrase, was introduced to compete with the polymerase, only allowing the fast, perfect matched primer extension to occur. The aim was to develop a method for analysis of around twenty loci in hundreds of samples in a high-throughput microarray format. A genotyping method for human papillomavirus has been developed, based on a combination of multiplex competitive hybridization (MUCH) and apyrase-mediated allele-specific extension (AMASE). Human papillomavirus (HPV), which is the causative agent in cervical cancer, exists in over a hundred different types. These types need to be determined in clinical samples. The developed assay can detect the twenty-three most common high risk types, as well as semi-quantifying multiple infections, which was demonstrated by analysis of ninety-two HPV-positive clinical samples. More stringent conditions can be obtained by increased reaction temperature. To further improve the genotyping assay, a thermostable enzyme, protease, was introduced into the allele-specific extension reaction, denoted PrASE. Increased sensitivity was achieved with an automated magnetic system that facilitates washing. The PrASE genotyping of thirteen SNPs yielded higher conversion rates, as well as more robust genotype scoring, compared to ASE. Furthermore, a comparison with pyrosequencing, where 99.8 % of the 4,420 analyzed genotypes were in concordance, indicates high accuracy and robustness of the PrASE technology. Single cells have also been analyzed by the PrASE assay to investigate loss of alleles during skin differentiation. Single cell analysis is very demanding due to the limited amounts of DNA. The multiplex PCR and the PrASE assay were optimized for single cell analysis. Twenty-four SNPs were genotyped and an increased loss of genetic material was seen in cells from the more differentiated suprabasal layers compared to the basal layer. / QC 20100714

In chronic lymphocytic leukemia (CLL), the presence of multiple subsets expressing ‘stereotyped’ B-cell receptors (BCRs) has implicated antigen(s) in leukemogenesis. These stereotyped subsets display similar immunoglobulin (IG) gene usage, almost identical complementarity determining region 3’s and may share clinical features. For instance, subsets #1 (IGHV1/5/7/IGKV1-39) and #2 (IGHV3-21/IGLV3-21) have inferior outcome compared to non-subset patients, whereas subset #4 (IGHV4-34/IGKV2-30) display a favourable prognosis. The aim of this thesis was to investigate genomic aberrations, gene expression patterns and methylation profiles in stereotyped subsets and compare epigenetic profiles in CLL and mantle cell lymphoma (MCL). In paper I, we investigated genomic aberrations in subsets #2, #4 and #16 and in non-stereotyped samples (n=101) using high-density 250K SNP arrays. Subset #2 and non-subset #2 IGHV3-21 cases displayed a higher frequency of aberrations than subset #4 cases. The high incidence of del(11q) in both subset #2/non-subset #2 may reflect the adverse survival reported for IGHV3-21 patients. In contrast, the lower frequency of genetic events and lack of poor-prognostic aberrations in subset #4 may partially explain their indolent disease. In paper II, we analysed the global RNA expression in subset #4, #16 and non-subset IGHV4-34 CLL patients (n=25). Subsets #4 and 16 showed distinct gene expression profiles, where genes involved in cell regulatory pathways were significantly lower expressed in subset #4, in line with their low-proliferative disease. In paper III, a genome-wide methylation array was applied to investigate methylation profiles in subsets #1, #2 and #4 (n=39). We identified differential methylation patterns for all subsets and found affected genes to be involved in e.g. apoptosis and therapy resistance. When performing functional annotation, a clear enrichment of genes involved in adaptive immunity was observed. These genes were preferentially methylated in subset #1 when compared to either subset #2 or #4, possibly due to different antigen responses. In paper IV, the genome-wide methylation profiles for 30 CLL and 20 MCL patients were investigated. Distinct methylation profiles were observed, where MCL displayed a more homogeneous profile. Homeobox transcription factor genes showed a higher degree of methylation in MCL, while apoptosis-related genes and proliferation-associated genes were methylated in CLL. In summary, this thesis demonstrates that stereotyped CLL subsets display differences in gene expression profiles, genetic aberrations and methylation patterns, underscoring the functional relevance of subgrouping according to BCR stereotypy. The distinct methylation profiles of CLL and MCL suggests that different epigenetic mechanisms are involved in the pathogenesis of these B-cell malignancies.

Bayesian methods are often criticized on the grounds of subjectivity. Furthermore, misspecified priors can have a deleterious effect on Bayesian inference. Noting that model selection is effectively a test of many hypotheses, Dr. Valen E. Johnson sought to eliminate the need of prior specification by computing Bayes' factors from frequentist test statistics. In his pioneering work that was published in the year 2005, Dr. Johnson proposed using so-called local priors for computing Bayes? factors from test statistics. Dr. Johnson and Dr. Jianhua Hu used Bayes' factors for model selection in a linear model setting. In an independent work, Dr. Johnson and another colleage, David Rossell, investigated two families of non-local priors for testing the regression parameter in a linear model setting. These non-local priors enable greater separation between the theories of null and alternative hypotheses. In this dissertation, I extend model selection based on Bayes' factors and use nonlocal priors to define Bayes' factors based on test statistics. With these priors, I have been able to reduce the problem of prior specification to setting to just one scaling parameter. That scaling parameter can be easily set, for example, on the basis of frequentist operating characteristics of the corresponding Bayes' factors. Furthermore, the loss of information by basing a Bayes' factors on a test statistic is minimal. Along with Dr. Johnson and Dr. Hu, I used the Bayes' factors based on the likelihood ratio statistic to develop a method for clustering gene expression data. This method has performed well in both simulated examples and real datasets. An outline of that work is also included in this dissertation. Further, I extend the clustering model to a subclass of the decomposable graphical model class, which is more appropriate for genotype data sets, such as single-nucleotide polymorphism (SNP) data. Efficient FORTRAN programming has enabled me to apply the methodology to hundreds of nodes. For problems that produce computationally harder probability landscapes, I propose a modification of the Markov chain Monte Carlo algorithm to extract information regarding the important network structures in the data. This modified algorithm performs well in inferring complex network structures. I use this method to develop a prediction model for disease based on SNP data. My method performs well in cross-validation studies.

In der vorliegenden Arbeit untersuchten wir an einer europäischen Population ausgewählte Polymorphismen zweier Gene auf eine Assoziation zu IA. Beide Gene FIGF und ACE2 sind lokalisiert auf Chromosom Xp22 und stellen damit positionelle Kandidatengene dar, aber auch funktionell sind sie von Interesse, da sie v.a. in Prozesse des Gefäßwachstums (FIGF) und der Blutdruckregulierung (ACE2) involviert sind; Vorgänge also, die möglicherweise in die pathophysiologische Erklärung der IA Entstehung mit hineinspielen. In keinem der insgesamt neun analysierten Polymorphismen konnten wir jedoch eine signifikante Assoziation zu IA finden. Auch eine Analyse möglicher intra- und intergenetischer Haplotypen aller untersuchten Varianten erbrachte kein signifikantes Ergebnis.

<p>Nucleic acid technology has assumed an essential role invarious areas of<i>in vitro</i>diagnostics ranging from infectious diseasediagnosis to human genetics. An important requirement of suchmolecular methods is that they achieve high sensitivity andspecificity with a fast turnaround time in a cost-effectivemanner. To this end, in this thesis we have focused on thedevelopment of sensitive nucleic acid strategies thatfacilitate automation and high-throughput analysis.</p><p>The success of nucleic acid diagnostics in the clinicalsetting depends heavily on the method used for purification ofthe nucleic acid target from biological samples. Here we havefocused on developing strategies for hybridisation capture ofsuch templates. Using biosensor technology we observed that thehybridisation efficiency could be improved using contiguousoligonucleotide probes which acted co-operatively. Byimmobilising one of the probes and annealing the second probein solution, we achieved a marked increase in target capturedue to a base stacking effect between nicked oligonucleotidesand/or due to the opening up of secondary structure. Suchco-operatively interacting modular probes were then combinedwith bio-magnetic bead technology to develop a capture systemfor the extraction of hepatitis C RNA from serum. Viral capturewith such co-operatively interacting probes extracted 2-foldmore target as capture with only a single probe achieving asimilar sensitivity to the conventional extraction protocol. Ananalogous strategy was designed to enrich for sequencingproducts prior to gel electrophoresis removing sequencingreagents and template DNA which interfere with the separationand detection of sequencing ladders, especially in the case ofcapillary gel electrophoresis. This protocol facilitates highthroughput clean-up of cycle sequencing reactions resulting inaccurate sequence data at a low cost, which is a pre-requisitefor large-scale genome sequencing products.</p><p>Currently, a large effort is directed towards differentialsequencing to identify mutations or polymorphisms both in theclinical laboratory and in medical genetics. Inexpensive, highthroughput methods are therefore required to rapidly screen atarget nucleic acid for sequence based changes. In the clinicalsetting, sequence analysis of human immunodeficiency virus(HIV-1) is used to determine the presence of drug resistancemutations. Here we describe a bioluminometric pyrosequencingapproach to rapidly screen for the presence of drug resistancemutations in the protease gene of HIV-1. This sequencingstrategy can analyse the protease gene of HIV-1 from eightpatients in less than an hour and such non-gel based approachesshould be useful in the future in a clinical setting for rapid,robust mutation detection.</p><p>Microarray technology facilitates large-scalemutation/polymorphism detection and here we developed amicroarray based single nucleotide polymorphism (SNP)genotyping strategy based on apyrase mediated allele specificextension (AMASE). AMASE exploits the fact that mismatchedprimers exhibit slower reaction kinetics than perfectly matchedprimers by including a nucleotide degrading enzyme (apyrase)which results in degradation of the nucleotides before themismatched primer can be extended. We have successfully typed200 genotypes (14% were incorrect without apyrase) by AMASEwhich cluster into three distinct groups representing the threepossible genotypes. In the future, AMASE on DNA microarraysshould facilitate association studies where an accuracy>99%is required.</p><p><b>Keywords:</b>nucleic acid capture, modular probes,biosensor, bio-magnetic separation, hepatitis C, sequencing,pyrosequencing, mutation detection, HIV-1, drug resistance,SNP, allele-specific extension, apyrase, genotyping.</p>

Προβλήματα υπογονιμότητας αντιμετωπίζει το 15% των ζευγαριών, εκ των οποίων το 40%-50% οφείλεται στον ανδρικό παράγοντα. Περιπτώσεις ανδρικής υπογονιμότητας στις οποίες δεν ανευρίσκεται προφανής αιτιολογικός παράγων, αντιπροσωπεύουν το 15% των περιπτώσεων και αναφέρονται ως περιπτώσεις ιδιοπαθούς υπογονιμότητας. Παλαιότερες αλλά και πιο πρόσφατες πληθυσμιακές μελέτες ανέδειξαν γενετικούς παράγοντες ως υπεύθυνους για τον φαινότυπο ορισμένων περιστατικών ιδιοπαθούς υπογονιμότητας και επομένως η μελέτη του γενετικού υπόβαθρου των ανδρών αυτών μπορεί να συμβάλλει στην διερεύνηση του παθογενετικού μηχανισμού της υπογονιμότητας/στειρότητας που παρουσιάζουν. Ειδικότερα, έχει διαπιστωθεί ότι ελλείμματα στις AZF περιοχές του Υ χρωμοσώματος υπάρχουν σε ένα ποσοστό 2% - 11% των υπογόνιμων ανδρών αυτής της κατηγορίας. Επίσης, σε πολύ πρόσφατη μελέτη προσδιορίστηκε η παρουσία ενός απλού νουκλεοτιδικού πολυμορφισμού SNP G197T που εντοπίζεται στο τέλος του πρώτου εξονίου του γονιδίου της πρωταμίνης-1. Ο πολυμορφισμός αυτός οδηγεί σε αντικατάσταση μιας συντηρημένης αργινίνης από σερίνη στην αμινοξική αλληλουχία της πρωταμίνης-1 (R34S), με ενδεχόμενες συνέπειες στο πακετάρισμα και την ακεραιότητα του DNA στην κεφαλή του σπερματοζωαρίου, γεγονότα, που μπορεί να οδηγήσουν σε ιδιοπαθή υπογονιμότητα. Τα αποτελέσματά μας έδειξαν ότι μόνο 3 από τα 100 άτομα (3%) έφεραν ελλείμματα στο Y χρωμόσωμα, ειδικότερα ένα άτομο με ενδιάμεση ολιγοσπερμία έφερε ελλείμματα στις AZFa και AZFb περιοχές και δυο άτομα με αζωοσπερμία έφεραν ελλείμματα στην AZFc περιοχή. Παράλληλα, o πολυμορφισμός SNP G197T δεν ανευρεθεί σε κανένα δείγμα του εξεταζόμενου πληθυσμού. / Infertility affects 10%-20% of all couples attempting pregnancy, with men responsible in 40%-50% of these cases. Male infertility exhibits no obvious clinical or pathophysiological features in 15% of these cases and it is therefore characterized as idiopathic. Genetic studies have revealed deletions in the AZF regions of Y chromosome, which contain genes involved in spermatogenesis, in 2%-11% of men with idiopathic infertility. Recent studies, also correlate male idiopathic infertility with the presence of an heterozygous SNP (G197T ) at the end of the first exon of protamine-1 (PRM1) gene. This SNP converts one of the highly conserved arginine residue to serine residue (R34S) which can substantially alter both DNA binding and protamine to protamine interaction in the sperm nucleus leading to infertility through defective chromatin packaging in the sperm nucleus. The purpose of this study was to evaluate the frequency of deletions in the AZF regions of Υ chromosome and the contribution of the polymorphism SNP G197T in a local sample of 100 men attending the Urology Clinic of the Patras University Hospital for infertility problems of unknown aetiology. Our results revealed that three of our patients (3%) were found to bear deletions in the AZF regions of the Y chromosome, one patient with intermediate oligospermia had deletions in AZFa and AZFb regions and two patients with azoospermia had deletion in AZFc region. On the other hand, the polymorphism SNP G197T has no distribution to the idiopathic infertility of the population studied.