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Chronic and acute respiratory diseases pose a major problem for public health worldwide due to the high morbidity and mortality rates, while treatment options remain mostly symptomatic. The renin-angiotensin system (RAS) plays an important role in lung tissue, regulating pulmonary circulation and blood pressure, but also contributing to normal pulmonary function and development. Angiotensin-converting enzyme (ACE) and its homologous angiotensin-converting enzyme 2 (ACE2) are considered to be amongst the main RAS regulators and are highly expressed in the pulmonary vascular endothelium. This review discusses the impact of ACE and ACE2 functional gene polymorphisms on seven major pulmonary diseases, in terms of predisposition, course, and outcome, revealing their potential utility as both genetic markers and biomarkers. The discussed conditions include chronic obstructive pulmonary disease (COPD), pulmonary hypertension (PH), asthma, acute lung injury (ALI), acute respiratory distress syndrome (ARDS), lung cancer and pulmonary sarcoidosis (PS), as well as SARS-CoV-2 viral infection and COVID-19 disease. © 2022 International Institute of Anticancer Research. All rights reserved.

Introduction: Hypohidrotic ectodermal dysplasia (HED) is an X-linked recessive disorder, characterised by abnormally developed ectodermal tissues (sweat glands, enamel, hair, nails). HED is caused by mutations of the EDA1 gene (Xq13.1) which codes for ectodysplasin A, a transmembrane signalling protein, which plays a significant role in ectodermal differentiation. Here we present a case of prenatal testing for HED. Methods: An 11-month-old boy with no family history was clinically diagnosed with HED. Genomic DNA was isolated from the patient’s white blood cells, and the possible existence of mutations suspected for HED development was investigated by an NGS gene panel. Total DNA was also isolated from blood samples of his parents. After mutation detection and genetic counselling, a prenatal HED test was performed during the 12th week of the mother’s next pregnancy. Embryonic DNA was isolated from a sample of chorionic villi. Parts of the EDA1, AMELX (X chromosome), and SRY (Y chromosome) genes were amplified by PCR, using the corresponding primers. Results: The boy with HED was found to be a hemizygote for the c.595_613del (p. Pro199PhefsTer75) deletion in the EDA1 gene. The fetus was male (XY) that did not carry the pathological mutation. Conclusion: The initial diagnosis of a family member with HED in a case with no family history poses the question whether this type of ectodermal dysplasia is autosomal dominant (and the case is due to a de novo mutation), autosomal recessive, or X-linked recessive. Molecular detection of the responsible mutation allows proper genetic counselling, carrier testing, and prevention by prenatal testing. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Introduction: Oculodentodigital syndrome (ODDS) is a rare genetic disorder caused by mutations in the gap junction GJA1 gene encoding connexin-43 (chromosome 6q22). A typical ODDS case is presented. Material and Methods: A 40-year-old male patient was examined neurologically and genetically. He had a history of recent parieto-occipital leukodystrophy, some episodes of temporary hearing loss, and characteristic facial features of ODDS. Sequencing of the GJA1 gene was performed in patient’s total genomic DNA sample isolated from peripheral blood cells. Results: A novel heterozygous missense mutation (443G>A) was identified in the GJA1 gene, resulting in coding for a different amino acid (Arg148Gln). Conclusion: The molecular genetic analysis confirmed the diagnosis of ODDS. The novel mutation, located within a calmodulin binding region of connexin-43, probably affects proper channel function. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Introduction: Frontometaphyseal dysplasia 1 (FMD1) is a rare X-linked craniofacial syndrome belonging in the otopalatodigital spectrum of disorders. Here we present a case with severe FMD1 that was caused by a mutation in the FLNA gene located on Xq28. Methods: A diagnosis for FMD1 was clinically set for a 22-year-old male who presented with cranial hyperostosis with marked supraorbital ridge, hypertelorism, progressive mixed hearing loss, partial anodontia, scoliosis, generalized skeletal dysplasia, and muscle atrophy. The patient’s two older brothers had also severe FMD1 manifestations with generalized skeletal dysplasia, cranial hyperostosis, progressive hearing loss, and scoliosis, while their mother and maternal grandmother had some less prominent FMD1 signs. Total DNA was extracted from blood samples of the patient, his brothers, and his parents. Results: DNA sequencing of all 48 exons of the FLNA gene revealed a single-point mutation (3476A>C) in exon 22. The missense mutation changes an Asp codon into an Ala codon in amino acid position 1159. The patient’s two brothers had the same mutation, while their mother was a heterozygous carrier having both the mutant allele and the normal allele. Conclusion: The clinical diagnosis for FMD1 was confirmed by genetic analysis. It is evident that the FLNA gene product filamin A plays a critical developmental role in morphogenesis of several tissues being a cytoskeleton component, since mutations in its gene cause multiple manifestations and diverse disorders of the otopalatodigital spectrum. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Child and adolescent obesity constitute one of the greatest contemporary public health menaces. The enduring disproportion between calorie intake and energy consumption, determined by a complex interaction of genetic, epigenetic, and environmental factors, finally leads to the development of overweight and obesity. Child and adolescent overweight/obesity promotes smoldering systemic inflammation (“para-inflammation”) and increases the likelihood of later metabolic and cardiovascular complications, including metabolic syndrome and its components, which progres-sively deteriorate during adulthood. Exosomes are endosome-derived extracellular vesicles that are secreted by a variety of cells, are naturally taken-up by target cells, and may be involved in many physiological and pathological processes. Over the last decade, intensive research has been conducted regarding the special role of exosomes and the non-coding (nc) RNAs they contain (pri-marily micro (mi) RNAs, long (l) non-coding RNAs, messenger (m) RNAs and other molecules) in inter-cellular communications. Through their action as communication mediators, exosomes may contribute to the pathogenesis of obesity and associated disorders. There is increasing evidence that exosomal miRNAs and lncRNAs are involved in pivotal processes of adipocyte biology and that, possibly, play important roles in gene regulation linked to human obesity. This review aims to improve our understanding of the roles of exosomes and their cargo in the development of obesity and related metabolic and inflammatory disorders. We examined their potential roles in adipose tissue physiology and reviewed the scarce data regarding the altered patterns of circulating miRNAs and lncRNAs observed in obese children and adolescents, compared them to the equivalent, more abundant existing findings of adult studies, and speculated on their proposed mechanisms of action. Exosomal miRNAs and lncRNAs could be applied as cardiometabolic risk biomarkers, useful in the early diagnosis and prevention of obesity. Furthermore, the targeting of crucial circulating exosomal cargo to tissues involved in the pathogenesis and maintenance of obesity could provide a novel therapeutic approach to this devastating and management-resistant pandemic. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Background/Aim: Tic habit cough (THC) is not easily recognized and requires a high index of suspicion. Since there is evidence for stress-related etiology, the study presents our experience during the eight-year period of the recent Greek financial crisis. Patients and Methods: This is a descriptive prospective cross-sectional clinical study using a consistent approach to diagnosis, possible triggers and treatment options. Results: Fifty-one children (26 girls, age 9.5±3.1y) from a total of 3,793 new referrals for chronic cough fulfilled the criteria of THC (1.34%). Incidence rates per 1,000 person-years were 1.34 (95%CI=0.34-5.40), 3.91 (95%CI=1.86-8.19), 4.03 (95%CI=2.01-8.06) and 14.60 (95%CI=10.43-20.44) for every two years. Poisson analysis showed an increased trend during the four time periods with an incidence rate ratio equal to 2.21 (95%CI=1.58-3.09, p

Background: One of the most common genetic causes associated with thrombophilia is mutation G20210A of the coagulation factor II (F2) gene. Materials and methods: Data collected from 355 unrelated Greeks examined for the mutation G20210A over a period of two decades were anonymously analyzed. Results: The statistical analysis confirmed the importance of F2 G20210A in thrombosis and the significance of a positive family history of thrombosis. An interesting finding was the increased prevalence of G20210A in men with thrombotic events aged >40 years. Conclusions: This study highlighted the great value of a positive family history of thrombosis and the importance of testing for this common mutation as a putative prevention strategy and a future biomarker for thrombophilia. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Introduction: Spastic paraplegia type 3 (SPG3) is a common autosomal dominant neurogenetic disease, presenting during childhood with symptoms of mildly progressive spasticity and weakness of the lower limbs. SPG3 develops due to mutations of the ATL1 gene that encodes atlastin-1, a GTPase crucial for the function of dendrites of corticospinal neurons. Here we present a case of preimplantation genetic testing for SPG3. Patient and methods: A 30-year-old woman with clinical symptoms of autosomal dominant spastic paraplegia since her first year of life asked for genetic counselling. DNA sequencing revealed the existence of mutation c.715C>T (p. R239C) in the ATL1 gene, confirming the diagnosis of SPG3. The patient asked for preimplantation testing for SPG3 after in vitro fertilization. An allele-specific method of PCR amplification was created in order to distinguish the mutant and the normal allele in the patient and her mother who also had SPG3, while her normal father served as control. The same nested PCR approach was used for the preimplantation testing of 11 available embryos. Results: The presence of the c.715C>T (p. R239C) mutation in the ATL1 gene was found in five embryos while six embryos carried normal alleles and were selected for IVF implantation. After three failed gestation attempts and one pregnancy ended by a spontaneous miscarriage in the first trimester due to a chromosomal abnormality, there was an achieved pregnancy with a totally normal embryo. Conclusion: SPG3 may be degrading to a patient’s quality of life; therefore, appropriate genetic counselling and preimplantation molecular testing may be provided as an option of prevention in offspring. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Cytokines involved in inflammatory and immune response have been associated with risk for development of basal cell carcinoma (BCC). In this study, three functional DNA polymorphisms affecting gene expression were investigated in 54 BCC patients and 111 healthy controls: interleukin-1b (IL-1b) +3953C/T, interleukin-10 (IL-10) − 1082G/A and angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphisms. Significant increase of the variant alleles was observed in IL-10 − 1082G (P = 0.019) and in ACE D (P = 0.003) in BCC patients in comparison to controls. Multivariate logistic regression models evaluated the contribution of homozygous and heterozygous variant polymorphisms to the risk for BCC development. The studied polymorphisms influencing the expression of IL-10 and ACE genes were recognized as potential predictive factors for BCC. These findings suggest a possible molecular mechanism leading to BCC development that is likely to involve the activation of angiotensin receptors in combination with increased plasma levels of IL-10 in patients. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.

Idiopathic pregnancy complications pose a major threat to both maternal and fetal health worldwide. Numerous studies have implicated the role of the renin-angiotensin system (RAS) in the development of obstetric syndromes, since it is crucial for the uteroplacental function. A major RAS component is the angiotensin-converting enzyme (ACE), which hydrolyses angiotensin I to angiotensin II, and not only regulates arterial pressure, but also fibrinolytic activity, indirectly, through the expression of plasminogen activator inhibitor-1. A key functional polymorphism of the ACE gene is the insertion/deletion (I/D) polymorphism, which affects gene expression and product levels, and can therefore lead to high blood pressure and/or reduced fibrinolytic activity. These can cause major pregnancy complications, such as preeclampsia, recurrent pregnancy loss and preterm birth. This review discusses how the ACE I/D is associated with susceptibility towards pregnancy complications, on its own or in combination with other functional gene polymorphisms such, as the angiotensin II receptor type 1 (AT1R) A1166CC, angiotensin II receptor type 2 (AT2R) G1332A, plasminogen activator inhibitor-1 (PAI-1) 4G/5G, matrix metallopeptidase- 9 (MMP-9) C1562T, angiotensinogen (AGT) M235T, renin (REN) 83A/G, factor XIII (F13) Val34Leu and endothelial nitric oxide synthase (eNOS) 4a/b. © 2021 International Institute of Anticancer Research. All rights reserved.

Introduction: Chromosome 18q deletion syndrome (18q-) is a rare chromosomal disorder with phenotypic variability, including mental deficiency, short stature, hypotonia, cleft palate, and hearing impairment. We present a case with features of 18q- syndrome who had combined 18q partial monosomy and 18p partial trisomy. Material and Methods: A 50-year-old female patient was examined during the genetic counseling of her brother. She had a history of congenital cleft palate and developmental deficiency with hypotonia, hearing loss, and epilepsy until adulthood. Her family history was free of related cases. Karyotype analysis and comparative genomic hybridization array (aCGH) were performed in patient’s blood samples. Results: Clinical examination showed features of 18q- syndrome including hypotonia and tremor. Neuropsychological deficiency of moderate cognitive disorder was noticed. The patient’s karyotype was normal. The aCGH analysis revealed 8 Mb deletion (del18q22.3q23) and 7.2 Mb duplication (dup18p11.32p11.23). Conclusion: Almost all patients’ clinical features were associated with 18q- syndrome. There are very few reported cases with similar genotype possibly caused by a de novo unequal recombination mechanism. © Springer Nature Switzerland AG 2020.

MicroRNAs (miRNAs) are small non-coding RNA molecules of about 20–22 nucleotides. After their posttranscriptional maturation, miRNAs are loaded into the ribonucleoprotein complex RISC and modulate gene expression by binding to the 3′ untranslated region of their target mRNAs through base-pairing, which in turn triggers mRNA degradation or translational inhibition. There is mounting evidence that miRNAs regulate various biological processes, including cell proliferation, differentiation, and apoptosis. Several studies have shown that miRNAs play an important role in neurogenesis and brain development. This review discusses recent progress on understanding the implication of precisely regulated miRNA expression in normal brain development and function. In addition, it reports known cases of dysregulation of miRNA expression and function implicated in the pathogenesis of neurodevelopmental disorders, craniofacial dysmorphic syndromes, neurodegenerative diseases, and psychiatric disorders. Current knowledge regarding the role of miRNAs in the brain in conjunction with the complex interplay between genetic and epigenetic factors are discussed. © Springer Nature Switzerland AG 2020.

X-linked spinal and bulbar muscular atrophy (SBMA), also known as Kennedy syndrome, is an adult-onset neurodegenerative disorder characterized by slowly progressive muscle atrophy and other severe symptoms gradually leading to reduced mobility and ultimately to death due to respiratory failure. Two decades ago we reported the first prenatal diagnosis of SBMA worldwide. Here we present a Greek family in which we have performed seven prenatal DNA tests for SBMA mutation after extensive genetic counseling. Since there is not yet a cure for SBMA, prenatal testing may be a good choice for couples at risk for prevention of this neurodegenerative disorder in their offspring. The issues addressed during genetic counseling for such a disabling disorder of adult onset are discussed as a paradigm for other conditions with similar characteristics. © Springer Nature Switzerland AG 2020.

Animal models are valuable tools for studying human cancer as well as for preclinical trials. The hamster model of chemically induced sequential oral carcinogenesis was developed by our group a decade ago in order to study the multistep process of alterations in gene expression during carcinogenesis. The purpose of this review was to discuss the utility of the hamster model of sequential oral carcinogenesis regarding the deciphering of the main pathways altered. An extended search for articles that cited that specific animal models was performed. Many studies have used the hamster model of sequential oral carcinogenesis either for evaluation of the expression of biomarkers alone, or for applying chemopreventive compounds and other therapeutic methods, or combining the use of biomarkers with the anticancer effect of some compounds. It seems that this animal model is indeed a useful tool that enables the study of cell biology, pathology and therapeutics of oral cancer. © 2019 International Institute of Anticancer Research. All rights reserved.

Background/Aim: Basal cell carcinoma (BCC) has been genetically associated with an increased expression of angiotensin-converting enzyme (ACE), an important factor of the renin-angiotensin system which produces vasoconstrictor angiotensin II. Other factors of this system include angiotensinogen (AGT) and angiotensin receptors AGTR1, AGTR2. We investigated the possible association of BCC with genetic variability in the AGT, AGTR1 and AGTR2 genes. Materials and Methods: DNA samples of 190 Greeks were studied, including 91 patients with BCC and 99 matched healthy controls. Molecular genotyping of patients and controls was performed for the polymorphisms AGT M235T, AGTR1 A1166C and AGTR2 G1675A. Results: The mutant T allele that increases AGT gene expression was detected in two-fold increased frequency in BCC patients in comparison to healthy controls (p

Heredity and reproduction have always been matters of concern. Eugenics is a story that began well before the Holocaust, but the Holocaust completely changed the way eugenics was perceived at that time. What began with Galton (1883) as a scientific movement aimed at the improvement of the human race based on the theories and principles of heredity and statistics became by the beginning of the 20th century an international movement that sought to engineer human supremacy. Eugenic ideas, however, trace back to ancient Greek aristocratic ideas exemplified in Plato’s Republic, which played an important role in shaping modern eugenic social practices and government policies. Both positive (encouragement of the propagation of the fit, namely without hereditary afflictions, i.e. socially acceptable) and negative (institutionalization, sterilization, euthanasia) eugenics focused on the encouragement of healthy and discouragement of unhealthy reproduction. All these practices were often based on existing prejudices about race and disability. In this article, we will focus on the rise of eugenics, starting with the publication of Origin of Species to the Holocaust. This examination will be multidisciplinary, utilizing genetics, legal history and bioethical aspects. Through this examination, we will discuss how provisional understandings of genetics influenced eugenics-based legislation. We will also discuss the rise of biopolitics, the change of medical ethos and stance towards negative eugenics policies, and the possible power of bioethical principles to prevent such phenomena. © 2019 Dimitra Chousou, Daniela Theodoridou, George Boutlas, Anna Batistatou, Christos Yapijakis, Maria Syrrou.

The association of the high blood pressure D variant of the angiotensin-converting enzyme (ACE) gene with medication-related jaw osteonecrosis (MRONJ) is described in two Greek patients. The first patient, a 73-year-old man, took zolendronate, 4 mg/100 ml IV once per month for two years for prostate cancer and bone metastases. Three months after drug discontinuation, extraction of the first premolar was performed. After the intervention, he suffered from osteonecrosis of the mandible. He presented with hypertension and genetic testing revealed that he was homozygous for the high blood pressure D variant of the ACE gene. The second patient, a 65 years old woman, took denosumab, 120 mg subcutaneously once per month for 6 months for possible bone metastases from breast cancer. Three months after extraction of the first molar, she suffered from MRONJ. He also presented with hypertension and genetic testing revealed that she had the high blood pressure D variant of the ACE gene in a heterozygous state, which moderately predisposes to hypertension. To our knowledge, this is the first report indicating that genetic predisposition to hypertension may increase risk for MRONJ. © 2019 International Institute of Anticancer Research. All Rights Reserved.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) due to mutations of the NOTCH3 gene is the most common cause of inherited cerebral small-vessel disease and one of the genetic causes of migraine with aura. The so-called CADASIL scale has been proposed as a clinical screening tool, and a score of 15 or higher seems useful in identifying patients with high probability of carrying NOTCH3 mutations. We studied a novel Greek family with clinical features compatible with CADASIL. Genetic analysis of NOTCH3 in the 2 living patients revealed the R182C mutation. Both patients had low scores (12 and 14) in the CADASIL scale, probably due to their relatively young age (38 and 37 years, respectively) at which cognitive decline and external capsule involvement have not developed yet. Another unusual feature in the second patient was a venous dysplasia in the parietal lobe. Observations presented here add to the notion that the CADASIL scale, although useful, probably needs a revision, taking into account the patient's age at which the score is calculated. © 2018 National Stroke Association

Sanitation and hygiene technologies have existed in ancient Hellas since the Bronze Age (ca. 3200– 1100BC), when extensive sewerage and drainage and other elaborate sanitary structures were known in Minoan palaces and towns. Classical and Hellenistic periods should be considered as the most progressive eras in the design of sanitary engineering. At that time anatomically shaped toilet seats are found in several sites since many private houses and public buildings have them. As cities grew in size the pressure of larger populations resulted in the construction of communal toilets with seats that were more densely packed together. Drainage and sewerage systems and sanitary installations reflect high cultural and technological levels and they are associated with contemporary observations and ideas about hygiene and medicine. Before the Hellenic advances, medicine was entirely confined to religious beliefs and metaphysical rituals. In the early Roman period, the knowledge of the ancient world on hygienic matter was incorporated in legislative rules. Despite the weakening of this legislation through the ages, the sanitation practices kept being applied even via a technical tradition of the masons. Later various rulers of the Hellenic world (Europeans or Ottomans), introduced their practices (traditional/scientific) sanitation in the greater Helladic regions. © 2017, IWA Publishing.

Cerebral venous thrombosis (CVT) is a severe multifactorial condition with various clinical manifestations that may include headache, papilledema, seizures, focal deficits, coma and death. The mortality rate of untreated CVT is up to 50%, but it drops to 10% when CVT is properly treated. Prevention of CVT is feasible through healthy lifestyle, genetic counseling, molecular genetic analysis for common thrombophilia-related mutations, and prophylactic anticoagulative medication. © Springer International Publishing AG 2017.

Neurofibromatosis-Noonan syndrome (NFNS) is a clinical entity possessing traits of autosomal dominant disorders neurofibromatosis type 1 (NF1) and Noonan syndrome (NS). Germline mutations that disrupt the RAS/MAPK pathway are involved in the pathogenesis of both NS and NF1. In light of a studied Greek family, a new theory for etiological pathogenesis of NFNS is suggested. The NFNS phenotype may be the final result of a combination of a genetic factor (a mutation in the NF1 gene) and an environmental factor with the epigenetic effects of muscle hypotonia (such as hydantoin in the reported Greek family), causing hypoplasia of the face and micrognathia. © Springer International Publishing AG 2017.

Huntington’s chorea or Huntington disease (HD) is a late-onset autosomal dominant neurodegenerative disorder caused by a trinucleotide repeat expansion. The multidisciplinary study of HD has been the focus of an international collaborating effort of basic and applied research for several decades. HD was the first human genetic disease mapped using linkage analysis of DNA polymorphisms and became a paradigm for scores of genes mapped in the same manner. Presymptomatic and prenatal testing have been available for HD families in the last 30 years, following genetic counseling and careful bioethical guidelines. Nevertheless, with the cure for the disease still elusive the uptake of predictive testing by at risk individuals is low. Current treatment of HD is mostly symptomatic, but ongoing observational studies, clinical trials and development of new gene silencing technologies have provided hopeful results. © Springer International Publishing AG 2017.

Aim: To study if the angiotensin receptor blocker olmesartan reduces levels of plasminogen activator inhibitor 1 (PAI1), a risk factor for oral cancer, in a mouse model and therefore whether it could be used in the treatment of this malignancy. Materials and Methods: Twelve transgenic PAI1 mice aged 16-20 weeks were divided in two groups each containing six animals. One group was given olmesartan every day for 30 days in drinking water in an amount corresponding to their weight, 0.005 mg/g, while the second group did not receive any medication (control group). Blood samples were obtained from animals of both groups, before and after one month of olmesartan administration and plasma PAI1 levels were measured using enzyme-linked immunosorbent assay. Results: In the olmesartan-treated group, a significant decrease of PAI1 level was found after 1 month of treatment (11.9±8.6 vs. 21.7±7.2 ng/ml, respectively; p=0.028). However, no statistically significant difference was observed in PAI1 levels between the olmesartan-treated and control groups after one month, (p=0.177). Conclusion: Olmesartan did not significantly affect PAI1 levels in this mouse model.

Aim: To describe the unusual presentation of a novel family with cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoancepahlopathy. Presentation of cases: The clinical features of five patients from three successive generations are described. The index patient presented with postpartum psychosis followed by cognitive decline. Brain imaging revealed no temporal pole involvement. Genetic testing was performed by full scan of the entire NOTCH3 gene revealing the R169C mutation. Multiple cardiovascular risk factors and late-onset strokes were present in the family. Conclusion: The combination of atypical psychiatric onset, absence of anterior temporal lesions, presence of cardiovascular risk factors and late-onset stroke may obscure the correct diagnosis for many years and requires a high index of suspicion. © 2016 Future Medicine Ltd.

Genes located on Y chromosome and expressed in testis are likely to be involved in spermatogenesis. TTTY2 is a Y-linked multicopy gene family of unknown function that includes TTTY2L2A and TTTY2L12A at Yq11 and Yp11 loci respectively. Using PCR amplification, we screened for TTTY2L2A- and TTTY2L12A-associated deletions, in 94 Greek men with fertility problems. Patients were divided into three groups as following: group A (n=28) included men with idiopathic moderate oligozoospermia, group B (n=34) with idiopathic severe oligozoospermia and azoospermia, and group C (n=32) with oligo- and azoospermia of various known etiologies. No deletions were detected in group C patients and 50 fertile controls. However, two patients from group A had deletions in TTTY2L2A (7.1%) and six in TTTY2L12A (21.4%), whereas from group B, four patients had deletions in TTTY2L2A (11.8%) and 10 in TTTY2L12A (29.4%). In addition, five patients from both groups A and B (8%) appeared to have deletions in both studied TTTY2 genes, although these are located very far apart. These results indicate that the TTTY2 gene family may play a significant role in spermatogenesis and suggest a possible mechanism of nonhomologous recombinational events that may cause genomic instability and ultimately lead to male infertility.