Non-genetic physicians' knowledge, attitudes and behavior towards medical genetics.

To examine the knowledge, behavior, and attitudes toward medical genetics among obstetrics and gynecology, pediatrics, and neurology residents and specialists, who encounter the highest number of patients with specific genetic disorders, in their everyday practice. The cross-sectional study involved 182 nongenetic residents and specialists in the Republic of Croatia, who completed a validated online questionnaire anonymously and voluntarily. The questionnaire consisted of five groups of questions: general information, knowledge, behavior in practice, attitude toward genetic testing, and additional education in medical genetics. The median score for overall knowledge of medical genetics was 70.2% among obstetrician-gynecologists, 80.5% among pediatricians, and 76.7% among neurologists (P < 0.001, lowest median in obstetrician-gynecologists). When asked about their behavior in daily practice, around 90% of respondents admitted the possibility of not recognizing patients with genetic disorders, which is why more than 90% emphasized the need for additional education in medical genetics. In addition, the respondents showed a positive attitude toward genetic testing, but they did not feel educated enough to interpret the results of genetic testing. The results highlight the need for further genetic education of non-genetic health professionals, which would lead to greater confidence and ability to recognize patients with genetic disorders, select the appropriate genetic testing method and achieve more efficient communication with patients.

Maternal LINE-1 DNA Methylation in Early Spontaneous Preterm Birth.

Despite considerable effort aimed at decreasing the incidence of spontaneous preterm birth (SPTB), it remains the leading cause of infant mortality and morbidity. The aim of this study was to evaluate maternal LINE-1 DNA methylation (DNAm), along with DNMT polymorphisms and factors proposed to modulate DNAm, in patients who delivered early preterm. This case-control study included women who delivered spontaneously early preterm (23-336/7 weeks of gestation), and control women. DNAm was analyzed in peripheral blood lymphocytes by quantification of LINE-1 DNAm using the MethyLight method. There was no significant difference in LINE-1 DNAm between patients with early PTB and controls. Among the investigated predictors, only the history of previous PTB was significantly associated with LINE-1 DNAm in PTB patients (ß = -0.407; R2 = 0.131; p = 0.011). The regression analysis showed the effect of DNMT3B rs1569686 TT+TG genotypes on LINE-1 DNAm in patients with familial PTB (ß = -0.524; R2 = 0.275; p = 0.037). Our findings suggest novel associations of maternal LINE-1 DNA hypomethylation with DNMT3B rs1569686 T allele. These results also contribute to the understanding of a complex (epi)genetic and environmental relationship underlying the early PTB.

The impact of needs-based education on the change of knowledge and attitudes towards medical genetics in medical students.

In this research we aimed to (1) develop and validate a new questionnaire examining attitudes and knowledge towards medical genetics, (2) examine the knowledge and attitudes towards medical genetics in students of the Medical Faculty in Rijeka, Croatia and (3) evaluate the impact of education from the mandatory course Medical Genetics on the change of knowledge and attitudes. The study was conducted on 191 fifth- and sixth-year students of the Integrated Undergraduate and Graduate University Study of Medicine in the academic year 2019/2020. Students completed the validated online questionnaire anonymously and voluntarily. Fifth-year students completed the questionnaire twice (beginning/end of the course), while sixth-year students completed the questionnaire once, 3 months after completing the course. The education was carefully designed for medical students according to the CoreCompetences in Genetics for Health Professionals in Europe issued by the European Society of Human Genetics. Using the Kruskal-Wallis test, a statistically significant difference was found between fifth year before and after education and between the fifth year before education and sixth year for (a) total knowledge (P < 0.001), (b) total attitudes (P < 0.001) and (c) personal assessment of knowledge in medical genetics (P < 0.001). Moreover, positive attitudes were associated with higher levels of knowledge. In conclusion, our results emphasise the importance of needs-based education in medical genetics for medical students, which is indispensable for the increase in the level of knowledge and development of positive attitudes in order to provide better health care for patients with genetic disorders.

Genetic variation in the maternal vitamin D receptor FokI gene as a risk factor for recurrent pregnancy loss.

PURPOSE: Recurrent pregnancy loss (RPL) is a reproductive disorder defined as the loss of two or more pregnancies before 24 weeks of gestation. Despite the fact that several mechanisms have been previously described for the pathogenesis of RPL, the causes of ∼50% of cases remain unknown. However, recent studies indicate association of vitamin D deficiency with adverse pregnancy outcome, including RPL. The vitamin D receptor (VDR) is a crucial mediator of the pleiotropic cellular effects of vitamin D. Its function is influenced by several single nucleotide polymorphisms (SNPs). The main objective of this study is to assess whether maternal VDR SNPs are associated with the risk of RPL in Slovenian and Croatian women. METHODS: A case-control study including 320 women with RPL and control women is designed to examine the potential association of VDR polymorphisms (FokI rs222857, Cdx2 rs11568820, and Taq1 rs731236) with RPL. Genotyping is performed using polymerase chain reaction and restriction fragment length polymorphism methods. RESULTS: We find a statistically significant higher frequency of the rs222857 CC genotype (χ2 = 6.61, p = .036) and C allele (χ2 = 5.93, p = .015) in RPL women compared to controls. Subsequently, the odds for RPL for the rs222857 are increased under the recessive (CCvsCT + TT: OR = 1.78; 95% CI = 1.12-2.82; p = .015) and the codominant (CCvsTT: OR = 2.21; 95% CI = 1.08-4.53; p = .029; CCvsCT: OR = 1.68; 95% CI = 1.04-2.72; p = .036) genetic models. The other two analyzed polymorphisms did not show any statistical significant result. CONCLUSIONS: Our results suggest that variations in the maternal VDR FokI gene might be associated with RPL in Slovenian and Croatian women.

Current State of Compulsory Basic and Clinical Courses in Genetics for Medical Students at Medical Faculties in Balkan Countries With Slavic Languages.

Introduction: In this study we aimed to perform the first research on the current state of compulsory basic and clinical courses in genetics for medical students offered at medical faculties in six Balkan countries with Slavic languages (Bosnia and Herzegovina, Croatia, Montenegro, North Macedonia, Serbia, and Slovenia). Materials and Methods: The study was conducted from June to September 2021. One representative from each country was invited to collect and interpret the data for all medical faculties in their respective country. All representatives filled a questionnaire, which consisted of two sets of questions. The first set of questions was factual and contained specific questions about medical faculties and design of compulsory courses, whereas the second set of questions was more subjective and inquired the opinion of the representatives about mandatory education in clinical medical genetics in their countries and internationally. In addition, full course syllabi were analysed for course aims, learning outcomes, course content, methods for student evaluation and literature. Results: Detailed analysis was performed for a total of 22 medical faculties in Bosnia and Herzegovina (6), Croatia (4), Montenegro (1), North Macedonia (3), Serbia (6), and Slovenia (2). All but the two medical faculties in Slovenia offer either compulsory courses in basic education in human genetics (16 faculties/courses) or clinical education in medical genetics (3 faculties/courses). On the other hand, only the medical faculty in Montenegro offers both types of education, including one course in basic education in human genetics and one in clinical education in medical genetics. Most of the basic courses in human genetics have similar aims, learning outcomes and content. Conversely, clinical courses in medical genetics are similar concerning study year position, number of contact hours, ECTS (European Credit Transfer and Accumulation System) and contents, but vary considerably regarding aims, learning outcomes, ratio of types of classes, teaching methods and student evaluation. Conclusion: Our results emphasise the need for future collaboration in reaching a consensus on medical genetics education in Balkan countries with Slavic languages. Further research warrants the analysis of performance of basic courses, as well as introducing clinical courses in medical genetics to higher years of study across Balkan countries.

Vitamin D receptor polymorphisms in spontaneous preterm birth: a case-control study.

AIM: To evaluate the association between the FokI (rs2228570), ApaI (rs7975232), Bsml (rs1544410), TaqI (rs 731236), and Cdx2 (rs11568820) single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) gene and spontaneous preterm birth (SPTB), as well as their effect on clinical characteristics of women with SPTB and their newborns. METHODS: This case-control study enrolled women who gave birth at the Department of Obstetrics and Gynecology, University Medical Center Ljubljana between 2010 to 2019. Cases were 118 women with spontaneous initiation of PTB after natural conception and 119 controls with a term singleton delivery after an uncomplicated pregnancy. The molecular analysis of VDR SNPs employed polymerase chain reaction and restriction fragment length polymorphism. RESULTS: Patients and controls did not significantly differ in the distribution of genotype or allele SNP frequencies. However, the FokI polymorphism had a significant effect on newborn birth weight in women with SPTB but not in controls (F=5.17, P=0.007, one-way ANOVA with post-hoc Scheffe test), with newborns of FokI TT carriers having the lowest birth weight (P=0.011). No other VDR SNP was associated with any other clinical characteristic of women with SPTB and their newborns. CONCLUSION: The TT genotype of the VDR FokI polymorphism is associated with newborn birth weight in women of European origin with SPTB.

DNMT3B rs1569686 and rs2424913 gene polymorphisms are associated with positive family history of preterm birth and smoking status.

AIM: To evaluate the association between spontaneous preterm birth (SPTB) and DNA methyltransferase (DNMT)1, 3A, 3B, and 3L gene polymorphisms, and their contribution to the clinical characteristics of women with SPTB and their newborns. METHODS: This case-control study, conducted in 2018, enrolled 162 women with SPTB and 162 women with term delivery. DNMT1 rs2228611, DNMT3A rs1550117, DNMT3B rs1569686, DNMT3B rs2424913, and DNMT3L rs2070565 single nucleotide polymorphisms were genotyped using polymerase chain reaction and restriction fragment length polymorphism methods. The clinical characteristics included in the analysis were family history of preterm birth, maternal smoking, maternal age, gestational week at delivery, and fetal birth weight. RESULTS: DNMT gene polymorphisms were not significantly associated with SPTB. DNMT3B rs1569686 and rs2424913 minor alleles (T) were significantly more frequent in women with familial PTB than in women with non-familial PTB, increasing the odds for familial PTB 3.30 and 3.54 times under dominant genetic models. They were also significantly more frequent in women with SPTB who smoked before pregnancy, reaching the most significant association under additive genetic models (odds ratio 6.86, 95% confidence interval 2.25-20.86, P<0.001; odds ratio 3.77, 95% confidence interval 1.36-10.52, P=0.011, respectively). CONCLUSIONS: DNMT3B rs1569686 and rs2424913 gene polymorphisms might be associated with positive family history of PTB and smoking status.

Combination of QF-PCR and aCGH is an efficient diagnostic strategy for the detection of chromosome aberrations in recurrent miscarriage.

BACKGROUND: Our aim was to conduct a comprehensive genetic evaluation using the combination of QF-PCR (quantitative fluorescence polymerase chain reaction) and aCGH (array comparative genomic hybridization) for the detection of the frequency and type of chromosome aberrations in recurrent miscarriage (RM) in the clinical setting. METHODS: This retrospective study was conducted on 73 first-trimester products of conception (POC) between September 2014 and February 2017. The POCs were collected from 73 women with at least one previous miscarriage and analyzed for chromosomal anomalies using QF-PCR and aCGH as part of the routine clinical evaluation. RESULTS: Chromosome aberrations were detected in 52/73 POCs (71.2%), of which 41 (56.2%) were identified by QF-PCR and an additional 11 (15.1%) by aCGH. Numerical aberrations constituted 92.3% of abnormalities, with trisomies as the most common subtype (72.9%). Causative structural aberrations were found in three samples (5.8%). The frequency of chromosome aberrations was not dependent on the number of previous miscarriages, whereas it significantly increased with advanced maternal age. CONCLUSION: Our results confirm that chromosome aberrations are the most common cause of RM and that QF-PCR and aCGH combination should be included in the routine genetic analysis of POCs of couples with miscarriage.

Matrix metalloproteinase and tissue inhibitors of metalloproteinases gene polymorphisms in disorders that influence fertility and pregnancy complications: A systematic review and meta-analysis.

Matrix metalloproteinase (MMP) and tissue inhibitors of metalloproteinase (TIMP) gene polymorphisms have been extensively evaluated as predisposing factors to human reproductive disorders. However, the evidence available is inconsistent. Therefore, we performed a systematic review and meta-analysis to provide the first comprehensive synopsis of case-control studies that investigated the association of MMP and TIMP gene polymorphisms with disorders that influence fertility and pregnancy complications. Literature search was performed using PubMed and Scopus databases. We included 42 case-control studies in the systematic review for the following disorders: adenomyosis, endometriosis, hypertensive disorders of pregnancy, preterm birth and recurrent spontaneous abortion. Although a large number of MMP and TIMP gene polymorphisms were tested, no exclusive and unambiguous risk factors were identified for any of the disorders. The majority of statistically significant associations were confirmed in just one study. Additionally, we performed two meta-analyses for MMP9 rs3918242 polymorphism in endometriosis/adenomyosis and preeclampsia but found no association with either disorder. Considering the modest associations and conflicting results between individual case-control studies, new data is needed for further research of this subject.

A Single Nucleotide Polymorphism of DNA methyltransferase 3B gene is a risk factor for recurrent spontaneous abortion.

PROBLEM: Aberrant DNA methylation has been suggested as a potential cause of recurrent spontaneous abortion (RSA). Considering the growing evidence on the important roles of DNA methylation in gametogenesis and early pregnancy, we investigated the potential association of DNA methyltransferase gene polymorphisms (DNMT1 rs2228611, DNMT3A rs1550117, DNMT3B rs1569686) with RSA in Slovenian reproductive couples. METHOD OF STUDY: A total of 146 couples with ≥3 consecutive spontaneous abortions and 149 control women and men with ≥2 normal pregnancies were included. Genotyping was performed using PCR-RFLP methods. RESULTS: We found a statistically significant higher frequency of the DNMT3B rs1569686 GG genotype (X2 =7.37;P = .025) and G allele (X2  = 6.33;P = .012) in RSA women compared with controls. Moreover, the odds for RSA in women were increased under the recessive genetic model (GGvsTG+TT: OR=1.92; 95% CI=1.18-3.09; P = .008). CONCLUSION: DNMT3B rs1569686 gene polymorphism in women might be a genetic marker for the susceptibility to RSA.

Systematic review and meta-analysis of genetic association studies in idiopathic recurrent spontaneous abortion.

OBJECTIVES: 1) To perform the first comprehensive systematic review of genetic association studies (GASs) in idiopathic recurrent spontaneous abortion (IRSA); 2) to analyze studies according to recurrent spontaneous abortion (RSA) definition and selection criteria for patients and control subjects; and 3) to perform meta-analyses for the association of candidate genes with IRSA. DESIGN: Systematic review and meta-analysis. SETTING: Not applicable. PATIENT(S): Couples with IRSA and their spontaneously aborted embryos. INTERVENTION(S): Summary odds ratios (ORs) were calculated by means of fixed- or random-effects models. MAIN OUTCOME MEASURE(S): Association of genetic variants with IRSA. RESULT(S): The systematic review included 428 case-control studies (1990-2015), which differed substantially regarding RSA definition, clinical evaluation of patients, and selection of control subjects. In women, 472 variants in 187 genes were investigated. Meta-analyses were performed for 36 variants in 16 genes. Association with IRSA defined as three or more spontaneous abortions (SAs) was detected for 21 variants in genes involved in immune response (IFNG, IL10, KIR2DS2, KIR2DS3, KIR2DS4, MBL, TNF), coagulation (F2, F5, PAI-1, PROZ), metabolism (GSTT1, MTHFR), and angiogenesis (NOS3, VEGFA). However, ORs were modest (0.51-2.37), with moderate or weak epidemiologic credibility. Minor differences in summary ORs were detected between IRSA defined as two or more and as three or more SAs. Male partners were included in 12.1% of studies, and one study included spontaneously aborted embryos. CONCLUSION(S): Candidate gene studies show moderate associations with IRSA. Owing to large differences in RSA definition and selection criteria for participants, consensus is needed. Future GASs should include both partners and spontaneously aborted embryos. Genome-wide association studies and large-scale replications of identified associations are recommended.

Functional single nucleotide polymorphisms of matrix metalloproteinase 7 and 12 genes in idiopathic recurrent spontaneous abortion.

PURPOSE: The aim of this study was to investigate the potential association of matrix metalloproteinase 7 (MMP7) -181 A/G and MMP12 -82 A/G functional single nucleotide polymorphisms (SNP) with idiopathic recurrent spontaneous abortion (IRSA) in Slovenian reproductive couples. METHODS: A case-control study was conducted on 149 couples with 3 or more consecutive idiopathic spontaneous pregnancy loses and 149 women and men with at least 2 live births and no history of pregnancy complications. Genotyping of MMP7 -181 A/G and MMP12 -82 A/G SNPs was performed using polymerase chain reaction and restriction fragment length polymorphism methods. RESULTS: There were no statistically significant differences in the distribution of MMP7 -181 A/G and MMP12 -82 A/G genotype, allele, or haplotype frequencies between IRSA patients and controls, as well as patients' primary and secondary IRSA. We also found no association of MMP7 -181 A/G and MMP12 -82 A/G genotypes, alleles, and haplotypes with IRSA. CONCLUSIONS: We found no evidence to support the association between IRSA and MMP7 -181 A/G and MMP12 -82 A/G SNPs in Slovenian reproductive couples.

Insertion/deletion polymorphism in intron 16 of ACE gene in idiopathic recurrent spontaneous abortion: case-control study, systematic review and meta-analysis.

The insertion/deletion (I/D) polymorphism in intron 16 of the angiotensin I-converting enzyme gene (ACE) has been extensively studied as a predisposing factor for idiopathic recurrent spontaneous abortion (IRSA). A case-control study including 149 women with ≥3 spontaneous abortions and 149 controls was performed to test the association of ACE I/D polymorphism with IRSA. A systematic review was conducted of previous case-control studies, with strict selection criteria for meta-analyses. We also aimed to evaluate the potential differences in summary estimates between studies defining IRSA as ≥2 and ≥3 spontaneous abortions. Genotyping was performed by PCR, and systematic review conducted using PubMed and Scopus. There was no association of the polymorphism with IRSA in Slovenian women. Sixteen case-control studies, showing substantial differences regarding IRSA definition and selection criteria for women were identified. Meta-analysis was performed and included four studies defining IRSA as ≥2 spontaneous abortions and the current study, which defined IRSA as ≥3 spontaneous abortions. Based on random effects model, meta-analysis conducted on 1192 patients and 736 controls showed no association with IRSA under dominant(DD+IDvsII) and recessive(DDvsID+II) genetic models. Well-designed studies are needed to evaluate the role of ACE I/D polymorphism in IRSA defined as ≥3 spontaneous abortions.

The -2549 insertion/deletion polymorphism in the promoter region of the VEGFA gene in couples with idiopathic recurrent spontaneous abortion.

PURPOSE: The vascular endothelial growth factor A (VEGFA) is crucial for normal vasculogenesis and angiogenesis during pregnancy, and alterations in the VEGFA gene expression were detected in women with idiopathic recurrent spontaneous abortion (IRSA) and spontaneously aborted conceptuses. Our aim was to evaluate whether there is an association between the functional -2549 insertion/deletion (I/D) polymorphism in the promoter region of the VEGFA gene and IRSA in reproductive couples. METHODS: We performed a case-control study involving 149 women and their 140 partners with three or more IRSA and 149 control women and men. Allele-specific polymerase chain reaction was used for genotyping. RESULTS: We found no association of the -2549 I/D polymorphism with IRSA in women. However, men with the DD genotype have a 1.75-fold increased risk of IRSA compared with men carrying the ID and II genotypes (95 % confidence interval (CI) = 1.05-2.93, P = 0.032). In addition, the D allele in men contributes to a 1.42-fold increased risk of IRSA (95 % CI = 1.02-1.97, P = 0.036) compared to men carrying the I allele. CONCLUSIONS: Our results indicate that the -2549 I/D polymorphism in the VEGFA gene in men might be associated with IRSA. Additional genetic association studies including both partners, as well as expression studies, are needed to elucidate the role of this polymorphism in IRSA.

Cornelia de Lange syndrome caused by heterozygous deletions of chromosome 8q24: comments on the article by Pereza et al. [2012].

In the March issue of the Journal in 2012, we reported on a girl with Langer-Giedion syndrome (LGS) phenotype and a 7.5 Mb interstitial deletion at 8q23.3q24.13, encompassing the EXT1, but not the TRPS1 gene. Recent discoveries have shown that heterozygous intragenic mutations or contiguous gene deletions including the RAD21 gene, which is located downstream of the TRPS1 gene, are the cause of Cornelia de Lange syndrome-4. Considering that the interstitial deletion in our patient included the RAD21 and 30 other RefSeq genes, we would like to suggest a revision of the diagnosis reported in our previous paper and compare our patient to other reported patients with Cornelia de Lange syndrome-4 caused by heterozygous deletions of chromosome 8q24. © 2015 Wiley Periodicals, Inc.

Functional polymorphisms of matrix metalloproteinases 1 and 9 genes in women with spontaneous preterm birth.

OBJECTIVE: The aim of this study was to investigate the association of functional MMP-1-1607 1G/2G and MMP-9-1562 C/T gene polymorphisms with spontaneous preterm birth (SPTB; preterm birth with intact membranes) in European Caucasian women, as well as the contribution of these polymorphisms to different clinical features of women with SPTB. METHODS AND PATIENTS: A case-control study was conducted in 113 women with SPTB and 119 women with term delivery (control group). Genotyping of MMP-1-1607 1G/2G and MMP-9-1562 C/T gene polymorphisms was performed using the combination of polymerase chain reaction and restriction fragment length polymorphism methods. RESULTS: There were no statistically significant differences in the distribution of neither individual nor combinations of genotype and allele frequencies of MMP-1-1607 1G/2G and MMP-9-1562 C/T polymorphisms between women with SPTB and control women. Additionally, these polymorphisms do not contribute to any of the clinical characteristics of women with SPTB, including positive and negative family history of SPTB, gestational age at delivery, and maternal age at delivery, nor fetal birth weight. CONCLUSION: We did not find the evidence to support the association of MMP-1-1607 1G/2G and MMP-9-1562 C/T gene polymorphisms with SPTB in European Caucasian women.

Insulin-like growth factor 2 and insulin-like growth factor 2 receptor gene polymorphisms in idiopathic male infertility.

OBJECTIVE: To test the association between insulinlike growth factor 2 (IGF2) ApaI and IGF2 receptor (IGF2R) Gly1619Arg gene polymorphisms and idiopathic male infertility. STUDY DESIGN: Polymerase chain reaction and restriction fragment length polymorphism methods were performed to detect the IGF2 ApaI and IGF2R Gly1619Arg genotypes in 98 Croatian men with idiopathic infertility and 113 fertile men. RESULTS: There were no significant differences between patients and controls according to genotype (chi2(IGF2) = 3.46, p = 0.177; chi2(IGF2R) = 1.12, p= 0.571, respectively) and allele frequencies (chi2(IGF2) = 3.23, p = 0.072; chi2(IGF2R) = 0.99, p = 0.319, respectively). Odds ratios for recessive, dominant and codominant models and association testing with each genotype combination revealed no difference between infertile men and controls. CONCLUSION: In this study we have shown that IGF2 ApaI and IGF2R Gly1619Arg gene polymorphisms are not associated with male infertility.

Genetic variation in tissue inhibitors of metalloproteinases as a risk factor for idiopathic recurrent spontaneous abortion.

OBJECTIVE: To investigate the potential association of tissue inhibitor of metalloproteinases (TIMP) 1, 2, 3, and 4 gene polymorphisms with idiopathic recurrent spontaneous abortion (IRSA). DESIGN: Case-control and association study. SETTING: Departments of gynecology and obstetrics and university-based research laboratory. PATIENT(S): A total of 149 couples with a history of three or more idiopathic spontaneous pregnancy losses and 149 fertile men and 149 fertile women with at least two live births and no history of pregnancy pathologies. INTERVENTION(S): Polymerase chain reaction and restriction-fragment-length polymorphism methods. MAIN OUTCOME MEASURE(S): Detection of TIMP-1 -372 C/T, TIMP-2 -303 C/T, TIMP-3 -915 A/G, TIMP-3 -1296 C/T, and TIMP-4 -3'-UTR C/T genotypes and allele frequencies. RESULT(S): There were no statistically significant differences in the distribution of any genotype and allele frequencies or any genetic model between IRSA patients and controls. Additionally, no significant associations occurred between combinations of TIMP polymorphisms and the risk of IRSA. CONCLUSION(S): We found no evidence for the association of TIMP-1, -2, -3, and -4 with IRSA in a Slovenian population.

Y chromosome azoospermia factor region microdeletions are not associated with idiopathic recurrent spontaneous abortion in a Slovenian population: association study and literature review.

OBJECTIVE: To investigate the potential association of Y chromosome microdeletions with idiopathic recurrent spontaneous abortion (IRSA) in a Slovenian population and compare our results with those of previously published studies in different populations, with the intention of clarifying the potential impact of Y chromosome microdeletions on IRSA. DESIGN: Case-control and association study. SETTING: Departments of gynecology and obstetrics and university-based research laboratory. PATIENT(S): Male partners of 148 couples with at least three spontaneous pregnancy losses of unknown etiology, and 148 fertile men. INTERVENTION(S): Multiplex polymerase chain reactions. MAIN OUTCOME MEASURE(S): Azoospermia factor (AZF) regions were tested for Y chromosome microdeletions according to European Academy of Andrology/European Molecular Genetics Quality Network guidelines. The PubMed database was searched to retrieve articles linking Y chromosome microdeletions and susceptibility to IRSA. RESULT(S): None of the IRSA or control men had microdeletions in the AZFa, AZFb, or AZFc regions. A total of nine previous studies examined the relationship between Y chromosome microdeletions and IRSA, yielding contradictory results, which we discuss in detail. CONCLUSION(S): On the basis of our comparisons, it is unlikely that Y chromosome microdeletions contribute to IRSA and are therefore currently not recommended for the routine evaluation of IRSA couples.