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Aneuploidy and isolated mild ventriculomegaly. Attributable risk for isolated fetal marker.

BACKGROUND: Does the prenatal ascertainment of isolated mild ventriculomegaly increase the a priori risk for aneuploidy when isolated or not associated with advanced maternal age? Does isolated mild ventriculomegaly increase the risk for pediatric developmental delay? METHODS: The Wayne State University (WSU) Reproductive Genetics abnormal case data base and the Madigan Army Medical Center (MAMC) experience were reviewed to compare the rates of aneuploidy for cases with fetal ventriculomegaly. Cases were classified by maternal age and associated sonographic markers of aneuploidy. Aneuploidy rates were compared between the isolated ventriculomegaly, ventriculomegaly with advanced maternal age (AMA), and ventriculomegaly associated with multiple anomalies. Rates of aneuploidy were compared to identify association. RESULTS: A total of 118 cases with ventriculomegaly were identified for comparison. Ninety-four cases were identified in the WSU cohort; 46 demonstrated isolated ventriculomegaly alone, and aneuploidy was present in 3/25 (12%) with invasive fetal testing, 0/24 (0%) cases in the MAMC cohort demonstrated aneuploidy. Isolated mild ventriculomegaly cases at MAMC were identified for further tests. DISCUSSION: Although the two study populations vary in age and risk distributions, the attributable risk for isolated mild ventriculomegaly poses a counseling conundrum due to the neurodevelopmental implication of this minor dysmorphism more so than its association with aneuploidy.

Aneuploidy↗

Parental decision-making differences between patients in two healthcare systems for choroid plexus cysts.

OBJECTIVE: We evaluated the medical-sociological implications of parental perception of risk and decision-making choices for prenatally ascertained choroid plexus cysts (CPCs) between two obstetric populations with similar clinical situations. METHODS: The Wayne State University (WSU) Reproductive Genetics database and the Madigan Army Medical Center (MAMC) experience were reviewed to compare the rates of aneuploidy and invasive testing for cases with CPC. Aneuploidy rates were compared between those with isolated CPC, CPC with advanced maternal age (AMA), and CPC associated with multiple anomalies. RESULTS: 186 cases were identified in the WSU cohort, of whom 27 (15%) declined invasive fetal testing. In the remaining 159 cases, aneuploidy was present in 2/132 (1.5%) isolated CPCs, 3/11 (27%) CPCs with AMA, and 15/16 (93%) CPCs with multiple anomalies. 107 cases were identified in the MAMC cohort, of whom 99 (92%) declined invasive fetal testing. No cases of aneuploidy were found in the 3/12 AMA cases or 5/95 non-AMA cases who underwent amniocentesis. CONCLUSIONS: The 2 cases of aneuploidy with isolated CPC cannot be ignored, and provide an estimated attributable risk of at least 0.8%, a higher risk than 38 years of age. However, the parental sociologic context may be as important as the genetic-prognostic risk for decision-making.

Academic Medical Centers↗

History of fetal diagnosis and therapy: Children's Hospital of Philadelphia experience.

Since its inception in 1995, the mission of the Center for Fetal Diagnosis and Treatment at the Children's Hospital of Philadelphia (CHOP) has been to provide comprehensive, multidisciplinary expertise in all facets of prenatal diagnosis, reproductive genetics, and prenatal, perinatal, and postnatal treatment for abnormal fetuses. Most of the authors were trained and/or served on faculty at centers in San Francisco (N.S.A., A.W.F., T.M.C., L.J.H.) or Detroit (A.W.F, M.P.J.). Accurate prenatal detection by serial sonographic study and the development of ultrafast magnetic resonance imaging (MRI) scanners has permitted delineation of the natural history of anatomic malformations. Definition of the pathophysiological features that affect clinical outcome and formulation of management based on prognosis has allowed families to make informed decisions. Outcomes have been improved through carefully planned and coordinated perinatal management. In some cases of life-threatening or severely debilitating defects, prenatal surgery has been offered.

Female↗

Sperm studies in heterozygote inversion carriers: a review.

The risk of producing unbalanced gametes in heterozygous inversion carriers mostly depends on the occurrence of recombination events within the inverted segment. Recombination determines the possibility of producing chromosomes with duplications/deficiencies (pericentric inversions) or with duplications/deficiencies which furthermore appear as dicentric and acentric fragments (paracentric inversions). In this work, a general description of the close relationship between the occurrence of crossovers in pericentric and paracentric inversions and the final segregation outcome is presented. After this introduction, a compilation of inversion segregation data and interchromosomal effect results from previously published sperm studies have been reviewed. Segregation results indicate a great heterogeneity in the percentage of unbalanced gametes, from 0 to 37.38%. The size of the inverted segments and their proportion in the chromosome are two parameters closely related with the incidence of recombination (P < 0.0001; using a quadratic model and Pearson's correlation test). These results suggest that the production of a significant level of unbalanced gametes would require a minimum inversion size of 100 Mbp and the inversion of at least 50% of the chromosome. Interchromosomal effects are seldom observed in chromosomal inversions. Finally, implications of the meiotic behavior of the inversions in the progeny of the carriers and the incorporation of sperm FISH segregation analysis for reproductive genetic counseling are discussed.

Chromosome Inversion↗

Advances in the prenatal and molecular diagnosis of the hemoglobinopathies and thalassemias.

Prenatal diagnosis is available for pregnancies at risk for virtually all inherited disorders of hemoglobin production. The field of reproductive genetics must confront many ethical, legal, and social concerns regarding its use, many of which derive from a woman's desire to bear children but legal right to abortion. The goal of more widespread utilization of prenatal diagnosis is sought in the context of questioning the ethical control to be exerted over the biological makeup of future generations. Its appropriate application would be facilitated greatly by the availability of reliable DNA markers of disease severity. Advances in fetal sampling and in detecting mutant globin genes have provided the safe, accurate methodology required for prenatal diagnosis. Chorionic villus sampling in the first trimester has become standard practice, but second trimester amniocentesis also is used for sampling fetal DNA. The use of preimplantation diagnosis and testing fetal cells from the maternal circulation will soon be practical. DNA-based detection of globin gene mutations has been facilitated greatly by the polymerase chain reaction revolution, and several reliable diagnostic methods are available. Polymerase chain reaction-based methods rely on restriction analysis, allele-specific hybridization or amplification, DNA sequence analysis, and new non-polymerase chain reaction methods for DNA amplification in vitro. These methods are available for detecting hemoglobinopathy, thalassemia, and thalassemic-hemoglobinopathy genes that affect alpha- or beta-globin loci.

Female↗

Determinants of parental decisions after the prenatal diagnosis of down syndrome: bringing in context.

This article develops the concept of decision context to refer to the combinations of factors that are important in understanding and predicting termination decisions after a prenatal diagnosis of trisomy 21. Four factors are examined: maternal age, gestational age, prior voluntary abortion, and existing children. The cases were studied at the Wayne State University's Reproductive Genetics Clinic. Qualitative comparative analysis, a technique specifically designed for examining the impact of combinations of factors, is used to isolate influential decision contexts. Odds and odds ratios are used to pinpoint outcome differences among different decision contexts. Four alternative decision contexts are especially conducive to choosing to terminate a pregnancy. Two of these involve women of any age and are formed from combinations of gestational age and existing children (existing children and low gestational age, and no children combined with late gestational age). Older women who have not had an abortion and who discover the trisomy 21 anomaly early are likely to choose termination. Younger women who have had an abortion are also likely to choose termination. Our data suggest there are added layers of complexity to patients' decisions that derive from combinations of conditions. An additional, strong implication is that qualitative comparative analysis may be particularly useful in understanding such complexity.

Abortion, Induced↗

[Neonatal aspects and risk factors in early intervention].

INTRODUCTION: Deficiency/disability in children is still a serious medical, social and human problem. A large number are related to the physiopathology of reproduction, genetics, pregnancy, delivery and the neonatal stage. DEVELOPMENT: Collaboration with obstetricians during the foetal period and their responsibility for the child at birth gives neonatology an important role in these problems. During hospitalization, often prolonged in children with problems, it is possible to diagnose, treat and attend deficiencies; and in other children who have a high risk of suffering deficiency, this can be defined more exactly as to it s degree of risk of severity. CONCLUSION: Whilst the child and his family are in hospital the deficiency or risk of deficiency may be defined, as may the social risks and anomalous family circumstances which may limit attention to children who are disabled or have a high risk of being so.

Child↗

Twins rate in the black-and-white cattle population in Lithuania.

Obtaining the maximal number of calves from each cow according to its natural genetic reproduction ability is the main condition of intensification of reproduction and increase of milk production. Twins rate in the black-and-white cattle population in Lithuania is 2.4%. Cows whose mothers have calved twins at least 1 time during reproductive life have twins in 5.6% of all calvings, the others--in 1.9%. Twins rate in separate bulls daughters range from 1% to 6.1%. Twins rate in cows range from 0.4% to 5% by separate bulls-getters. Productivity of 305 days lactation after having twins is better (551.2+/-68.1 kg of milk, 18.4 +/-2.9 kg of fat and 21.5+/-2.4 kg of protein, P < 0.001). The rate of twin births increases when lactation is increased. The influence of lactation on rate of twin births is 0.6% in total dispersion (P < 0.001). The influence of calving season on twins rate is statistically insignificant but the parts of twins by calving seasons are distributed differently.

Animals↗

The role of Cayo Santiago in primate field studies.

Cayo Santiago has provided the opportunity to study primate biology in a free-ranging neutral environment free of provocative human influences. Rarely, if ever, does such a situation occur in natural rhesus habitats in Asia. This Cayo Santiago advantage has permitted fine-scale analyses of the details of behavior, ecology, reproduction, genetics, demography, and pathobiology with a greater degree of precision than is possible in the field. At the same time, research on Cayo Santiago has provided valuable baselines for comparative work with natural populations in Asia. Field and laboratory work with the Cayo Santiago colony has produced an impressive number of pioneering studies, from the first investigations of Carpenter in the late 1930's, to the recent demonstrations of Kessler and Rawlins on the demographic role of tetanus in rhesus population ecology and the effectiveness of an inoculation program in eliminating infectious disease. Few, if any, primate colonies have had such a productive interface of naturalistic studies of behavior and ecology with basic biomedical research.

Academies and Institutes↗

Occupation and ovarian cancer: a case-control study in the Washington, DC, metropolitan area, 1978-1981.

Ovarian cancer risk factors may be genetic, reproductive, or hormonal in nature. Occupational exposure to talc and other carcinogenic substances has not been studied in relation to ovarian cancer risk. We therefore examined the job histories of 296 women aged 20 to 79 who were diagnosed with epithelial ovarian cancer in the Washington, DC area in 1978 to 1981, comparing them to 343 hospital controls, matched for age and race. A blind exposure assessment, evaluating each job/industry combination for potential exposure to talc, ionizing radiation, polycyclic aromatic hydrocarbons, and solvents was conducted by an industrial hygienist blind to case-control status. Women exposed to talc had a relative risk of ovarian cancer below the null, but the confidence interval was wide and there was no evidence of a trend. Women exposed to polycyclic aromatic hydrocarbons had an elevated relative risk, also with a wide confidence interval and no evidence of a trend with duration.

Adult↗

Milk urea nitrogen concentration: heritability and genetic correlations with reproductive performance and disease.

The objectives of this study were to estimate the heritability of milk urea nitrogen (MUN) concentration and describe the genetic relationship between MUN and reproductive performance and between MUN and diseases in Holsteins. Dairy Records Management Systems (Raleigh, NC) provided lactation data. The Danish Agricultural Advisory Center provided breeding value estimates for diseases. Infrared (IR) and wet chemistry (WC) data were analyzed separately. Heritabilities and genetic correlations for 2 different measures of MUN and reproductive performance were estimated with an animal model using ASREML. Heritabilities for MUN were estimated using all lactations combined (lactations 1 through 5) and separately for first lactation and second lactation. Genetic correlations with reproduction and health were estimated separately for parities 1 and 2. Herd-test-day or herd-year-season along with age at calving and days in milk were included as fixed effects in all models. Heritability estimates for all lactations combined were 0.15 for WC MUN and 0.22 for IR MUN. Genetic correlations between WC MUN and 2 measures of reproductive performance, days to first service, and first service conception were not different from zero. In contrast, the genetic correlation between WC MUN and days open of 0.21 in first lactation and 0.41 in second lactation indicated that higher WC MUN values were associated with increased days open. Correlations among estimated breeding values for MUN and estimated breeding values for Danish diseases identified no significant relationships. Although the results of this study indicate that heritable variation for MUN exists, the inability to identify significant genetic relationships with several measures of disease or reproductive performance appears to limit the value of MUN in selection for disease resistance and improved reproduction.

Animals↗

Flies across the water: genetic differentiation and reproductive isolation in allopatric desert Drosophila.

Between sister species of Drosophila, both pre- and postzygotic reproductive isolation commonly appear by the time a Nei's genetic distance of 0.5 is observed. The degree of genetic differentiation present when allopatric populations of the same Drosophila species exhibit incipient reproductive isolation has not been systematically investigated. Here we compare the relationship between genetic differentiation and pre- and postzygotic isolation among allopatric populations of three cactophilic desert Drosophila: D. mettleri, D. nigrospiracula, and D. mojavensis. The range of all three is interrupted by the Gulf of California, while two species, D. mettleri and D. mojavensis, have additional allopatric populations residing on distant Santa Catalina Island, off the coast of southern California. Significant population structure exists within all three species, but only for allopatric populations of D. mojavensis is significant isolation at the prezygotic level observed. The genetic distances for the relevant populations of D. mojavensis were in the range of 0.12, similar to that for D. mettleri whose greatest D = 0.11 was unassociated with any form of isolation. These observations suggest further investigations of Drosophila populations with genetic distances in this range be undertaken to identify any potential patterns in the relationship between degree of genetic differentiation and the appearance of pre- and/or postzygotic isolation.

Alleles↗

The importance of integrating genetic testing into reproductive medicine: a retrospective observational study investigating the monogenic causes of human infertility in couples considering ICSI.

The genetic landscape of human infertility is complex with diverse etiologies. Identifying the underlying etiology is crucial for guiding reproductive decisions and improving management for infertile couples. Here, we aim to report on the molecular spectrum of monogenic genetic causes of reproductive failure. Over a 3-year period, we recruited all infertile couples considering assisted reproductive technologies (ART) for whom the underlying genetic cause had been identified, in either partner, using exome sequencing (ES). Clinical data of all participants along with their hormonal profiles, sonographic findings and spermograms were recorded. The study included 50 couples with primary infertility. Clinically, male factor infertility was documented in 26 patients, female factor infertility in 10, while reproductive failure was unexplained in the remaining 14 couples. All participating couples had potentially disease-causing variants in infertility genes. ES identified variants related to male infertility in 26 men, while variants in female infertility-related genes were detected in the remaining couples (n&#x2009;=&#x2009;24). According to ACMG classification criteria, 78% (39/50) of couples harbored pathogenic/likely pathogenic (P/LP) variants, whereas 22% (11/50) carried variants of uncertain significance (VUS). In view of the identified genetic etiologies, the cohort was stratified into two groups based on the predicted reproductive outcome: (1) couples with significantly impaired reproductive potential, and (2) couples who can have biological children using appropriate medical interventions. However, classifications involving VUS were interpreted cautiously and considered exploratory. This study provides further evidence for the molecular heterogeneity of human infertility and highlights the usefulness of genetic testing for infertile couples pursuing ARTs.

Humans↗

Genetic diversity and reproductive success in mandrills (Mandrillus sphinx).

Recent studies of wild animal populations have shown that estimators of neutral genetic diversity, such as mean heterozygosity, are often correlated with various fitness traits, such as survival, disease susceptibility, or reproductive success. We used two estimators of genetic diversity to explore the relationship between heterozygosity and reproductive success in male and female mandrills (Mandrillus sphinx) living in a semifree ranging setting in Gabon. Because social rank is known to influence reproductive success in both sexes, we also examined the correlation between genetic diversity and social rank in females, and acquisition of alpha status in males, as well as length of alpha male tenure. We found that heterozygous individuals showed greater reproductive success, with both females and males producing more offspring. However, heterozygosity influenced reproductive success only in dominant males, not in subordinates. Neither the acquisition of alpha status in males, nor social rank in females, was significantly correlated with heterozygosity, although more heterozygous alpha males showed longer tenure than homozygous ones. We also tested whether the benefits of greater genetic diversity were due mainly to a genome-wide effect of inbreeding depression or to heterosis at one or a few loci. Multilocus effects best explained the correlation between heterozygosity and reproductive success and tenure, indicating the occurrence of inbreeding depression in this mandrill colony.

Animals↗

Reproductive biology and genetic diversity of a cryptoviviparous mangrove aegiceras corniculatum (Myrsinaceae) using allozyme and intersimple sequence repeat (ISSR) analysis

Mangroves consist of a group of taxonomically diverse species representing about 20 families of angiosperms. However, little is known about their reproductive biology, genetic structure, and the ecological and genetic factors affecting this structure. Comparative studies of various mangrove species are needed to fill such gaps in our knowledge. The pollination biology, outcrossing rate, and genetic diversity of Aegiceras corniculatum were investigated in this study. Pollination experiments suggested that the species is predominantly pollinator-dependent in fruit setting. A quantitative analysis of the mating system was performed using progeny arrays assayed for intersimple sequence repeat (ISSR) markers. The multilocus outcrossing rate (tm) was estimated to be 0.653 in a wild population. Both allozyme and ISSR were used to investigate genetic variation within and among populations. The combined effects of founder events and enhanced local gene flow through seedling dispersal by ocean currents apparently played an important role in shaping the population genetic structure in this mangrove species. Both allozyme variation (P = 4.76%, A = 1.05, HE = 0.024) and ISSR diversity (P = 16.18%, A = 1.061, HE = 0.039) were very low at the species level, in comparison with other woody plants with mixed-mating or outcrossing systems. Gene differentiation among populations was also low: allozyme GST = 0.106 and ISSR GST = 0.178. The unusually high genetic identities (0.997 for allozyme and 0.992 for ISSR loci), however, suggest that these populations are probably all descended from a common ancestral population with low polymorphism.

Journal Article↗

Secondary traits: sire evaluation and the reproductive complex.

Genetic aspects of dystocia, reproduction and its association with production, and calf livability are reviewed. Measures of each are presented. Genetic and maternal effects, sire evaluation by births from heifers and older cows, and correlations with production and type are discussed for dystocia. Heritabilities for measures of reproduction were low. Fertility and production were antagonistic in cows but complementary between heifer breedings and production in first lactation. There were differences among sires for calf mortality up to 48 h after birth, but heritabilities were low. Livability and dystocia are closely correlated genetically. Methods for multiple traits ideally should be used for sire evaluation.

Animals↗