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Query: UMLS:C0013080 (Down syndrome)
 14,180 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Studies have shown that fertility (defined as number of live births) declines with age in women. However, it is not known to what extent other factors, such as male reproductive capacity and coital patterns affect this decrease. Male fecundity may also decline with age, and coital frequency is believed to decline with length of marriage. All these factors are closely related to the woman's age. The effects of male fecundity and coital frequency can be eliminated in evaluating female fecundity by studying patients who have received artificial insemination and restricting the group to those with azoospermic husbands. In 2193 patients drawn from 11 centers in France that offer artificial insemination with frozen donor semen, women over 30 exhibited a marked decline in fecundity. The cumulative success rate after 12 cycles of insemination was 73% for those under 25, 74.1% for the 26-30 age group, 61.5% for those 31-35 years old, and 53.6% for those over 35 years. The difference in fecundity with age was consistent across the centers, an important factor to note since the mean success rate per cycle differed considerably among the participating centers. The decreased fecundity in women over 30 may be attributed to gynecologic diseases, or effects of age on the incidence of tubal deciliation and occurrence of ovulatory disorders. New guidelines for counseling on reproduction may be needed for women over 30. Currently, counseling regarding reproduction and maternal age is limited to increased risks of Down's syndrome and other genetic abnormalities and risks of spontaneous abortion and perinatal deaths. The age of a woman should be considered when deciding when to start an infertility workup or stop treatment for infertility, and in selecting appropriate candidates for tubal surgery and in vitro fertilization. There is also a need to reevaluate individual and societal goals regarding childbearing to accommodate women's desires to have both a family and a career.
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PMID:Female fecundity and age. 705 34

New reproductive genetics means recently developed techniques to prevent the birth of children with specific defects or genetic diseases by testing individuals for sickle cell anemia, the thalassemias, Tay-Sachs disease, cystic fibrosis, or Down syndrome. Third World health services have many deficiencies with high maternal mortality rates (30-40 fold higher than in developed countries), the low percentage of births delivered by health personnel, the high rates of low birth weight babies, and high child malnutrition and infant mortality rates. The main issues in women's reproductive health are fertility regulation, abortion, maternal mortality, sexually transmitted diseases, and infertility. As a result of expansion in contraceptive use worldwide, the total fertility rate in developing countries has declined from 6.1 in 1965 to 3.9 in 1990. It is estimated that, worldwide, 36-53 million induced abortions are performed each year, most of them in developing nations. WHO estimates that more than 500,000 women die each year because of complications of pregnancy, most in developing countries. More than 95% of the 13 million estimated deaths of children under 5 years of age have occurred in these countries. Approximately 200 million people carry a potentially pathologic hemoglobinopathy gene, and about 250,000 children are born every year with hemoglobinopathy, most of them in the developing world. Reproductive genetic testing in big cities and in private for-profit ventures cater to the socioeconomic elite. Amniocentesis is often misused for fetal sex determination to abort female fetuses in India. Currently, in Cuba virtually every pregnant woman is tested for sickle cell trait and maternal serum alpha-fetoprotein levels between 15 and 20 weeks of gestation. It is predicted that the judicious use of reproductive genetic testing will be possible when health and quality of life issues are addressed properly.
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PMID:Reproductive health and genetic testing in the Third World. 840

Each organ of a patient with the Down's Syndrome (trisomy 21) shows the pathology. One notices the specific features already with an infant. The life expectation of these children has increased considerably and it depends upon the appearance or not of a heart defect. The ventricular septum defect is most frequent but a small number of these patients show a complex cardiopathy. The incidence of pulmonary hypertension is also high. The obstruction of gastroenteric tract can cause problems from the prenatal phase onwards. The main endocrinological difficulties are dysfunction of the thyroid gland and also infertility. Ocular disorders like refraction disorders occur frequently. Due to decreased conduction, there is a hearing loss. The cellular immunity is clearly reduced, hence, the susceptibility to infections like hepatitis B, increases. The major oral problems are apparently oversized tongue and a high sensitivity to gingivitis.
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PMID:[Down syndrome: 1. Medical aspects]. 865 Mar 77

Among Palestinian Arabs the rate of consanguinity is very high and some 44.3% of the marriages are between relatives (22.6% of them between first cousins). In almost 2,000 files from Palestinian Arab families who attended the genetics clinic in the Hadassah Medical Center; we were able to study the effects of consanguinity on different disorders. The consanguinity rate in families with dominant or X-linked disorders and chromosome aberrations was similar to the one observed in the general population. We did not find any significant differences in the rate of consanguineous marriages between the parents and grandparents of children affected with trisomy 21 and the general population. Thus, we were not able to confirm the suggestion that there is an increase risk for trisomies in children/grandchildren of consanguineous parents. Among the parents of patients with rare autosomal recessive disorders the consanguinity rate was much higher than the one of the general population (92.5%). Among the autosomal recessive disorders, which were relatively frequent in the population, there were fewer marriages between relatives; but in most cases the difference from rare disorders is relatively small. The importance of genetic factors in various congenital malformations, such as neural tube defects and cleft lip/palate or in various forms of infertility, was confirmed by the observation of a significantly higher consanguinity rate in the parents of these patients than is observed in the general population.
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PMID:Genetic disorders among Palestinian Arabs: 1. Effects of consanguinity. 902 Oct 24

Cytogenetic surveys of neonates have found that approximately one boy in 500 is born with an extra sex chromosome. Some of these boys are now being diagnosed when prenatal karyotyping is done for the detection of Down syndrome and other major aneuploidies. This study estimates what proportion of those not detected prenatally will be diagnosed postnatally and what the indications for karyotyping are likely to be. We ascertained all 47,XXY and 47,XYY males detected prenatally and postnatally (during the 4 years 1990-1993) in the three cytogenetic laboratories in the North Thames (West) region. The age at diagnosis and indication for karyotyping were noted for cases diagnosed postnatally. Less than 10 per cent of the estimated number of affected fetuses were detected prenatally. This study suggests that most males born with these chromosome patterns will go through life without being karyotyped, that the commonest indication for a 47,XYY male to be karyotyped will be developmental delay and/or behaviour problems, and that the commonest indication for a Klinefelter male to be karyotyped will be hypogonadism and/or infertility. It would appear that most undiagnosed 47,XXY and 47,XYY males do not look or behave in a manner which prompts testing for a chromosome abnormality.
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PMID:47,XXY (Klinefelter syndrome) and 47,XYY: estimated rates of and indication for postnatal diagnosis with implications for prenatal counselling. 955 51

Clinical observations and epidemiological evidence suggest that important aetiopathological events that cause neoplastic transformation of the male germ cell may occur in fetal life or early infancy. The incidence of germ cell neoplasia is high in individuals with various disorders of gonadal development and sexual differentiation, such as gonadal dysgenesis or androgen insensitivity syndrome. Increased risk has also been noted in individuals with trisomy 21, idiopathic infertility and low birth weight. Infertility is sometimes associated with small aberrations of sex chromosomes (e.g. low frequency mosaicism XY/XO) which can also be found in patients with testicular cancer. The variety of conditions that predispose to testicular neoplasia and the rise in its incidence in many countries speaks for the influence of environmental factors which may affect genetically predisposed individuals. We hypothesise that if the development of the testis is disturbed or delayed, primordial germ cells or gonocytes undergo maturation delay or differentiation arrest which may render them susceptible to neoplastic transformation. Morphologically homogenous premalignant carcinoma in situ (CIS) cells have the potential to differentiate into a variety of histological forms of overt testicular tumours. Analysis of cell surface antigens expressed by CIS cells found in the vicinity of pure and mixed tumours demonstrates that CIS cells are phenotypically heterogeneous. Comparison of the phenotypes of CIS cells, primordial germ cells, human embryonal carcinoma cells and closely related primate embryonal stem cells reveals various similarities but also differences. We speculate that phenotypical heterogeneity of CIS cells may be associated with their potential to give rise to different tumour types, and may be related to the developmental stage of the early germ cell which has undergone malignant transformation.
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PMID:Developmental arrest of germ cells in the pathogenesis of germ cell neoplasia. 952 79

The aneuploid condition of patients with Down's syndrome (trisomy 21) frequently leads to a sub- or infertility of these individuals. Gonads from adults and fetuses with trisomy 21 demonstrated histologically a remarkable reduction in germ cells. Disorders in the germ cell migration, the early development of the gonads as well as meiotic defects are thought to contribute to this pathomorphology. To gain information about premeiotic defects, investigations on the trisomy 16 mouse, an animal model for Down's syndrome, were carried out. By means of morphometric studies a delay in migration and a reduction in primordial germ cells was evaluated in trisomic mice of embryonic day 11 (E11). At day E13 a generalized growth retardation of the developing gonads was obvious in trisomic animals. Additionally performed electron microscopic examinations revealed signs of germ cell demise in trisomy 16 mice. Thus, the mechanisms of a diminished proliferation capacity, impaired migration and premature death of germ cells represent premeiotic disorders that presumably contribute to the pathomorphology observed in the gonads of individuals with Down's syndrome.
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PMID:Germ cell migration and early development of the gonads in the trisomy 16 mouse--an animal model for Down's syndrome. 1036 6

Intracytoplasmic sperm injection (ICSI) with ejaculated, epididymal or testicular spermatozoa was first successful in 1992 and has since become the widely accepted treatment for couples with severe male-factor infertility. The outcome of several thousands of ICSI cycles in terms of fertilization, embryo cleavage and implantation is similar to that for conventional in-vitro fertilization in couples with tubal or idiopathic infertility. To evaluate the important issue of safety of the new technique of ICSI, a prospective follow-up study of 1987 children born after ICSI was carried out. The aim was to compile data on karyotypes, congenital malformations, growth parameters and developmental milestones. Parents' agreement to genetic counselling was obtained as well as prenatal diagnosis, followed by a physical examination of the children at 2 months, 1 year and 2 years. Between April 1991 and August 1997, 1699, 91 and 118 children were born after ICSI with ejaculated, epididymal and testicular spermatozoa respectively; 79 children were born from cryopreserved ICSI embryos. In all, 1082 karyotypes were determined by prenatal diagnosis, 18 of which were abnormal and de novo (1.66%) (nine each of autosomal and sex chromosomal aberrations), and 10 karyotypes (0.92%) were inherited structural aberrations. Of these, nine (eight balanced structural aberrations and one unbalanced trisomy 21) were transmitted from the father. Ten pregnancies were terminated after prenatal karyotyping or DNA testing. Forty-six major malformations (2.3%) were observed at birth. Seven malformations, observed by prenatal ultrasound, were terminated. Twenty-one (1.1 %) stillbirths, including four with major malformations, occurred later than 20 weeks of pregnancy. Mean gestational age at birth was 38.7 weeks for singletons, 36.0 weeks for twins and 32.0 weeks for triplets. No specifically higher incidence of malformations was found in any given subgroup.
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PMID:Seven years of intracytoplasmic sperm injection and follow-up of 1987 subsequent children. 1057 38

The wide use of assisted conception methods has risen dramatically. The greater proportion of singletons, twins and high order of multiplicity conceived by those methods have already focused the medical community to various obstetric complications. Recently, there have been suggestions that the levels of mid-gestation serum markers, particularly human chorionic gonadotrophin (HCG), might be affected by assisted conception, leading to higher false-positive results. Furthermore, women who conceived after assisted reproduction methods are on average older, and in many cases their current pregnancy was achieved after long-standing infertility and might even be their last one. This is why they are extremely wary of any invasive fetal karyotyping. Therefore, every effort should be made to provide them with the most accurate screening of Down's syndrome (DS) risk. In this respect, nuchal translucency (NT) measurement, which has been reported to be another effective screening method, might be a more reliable marker in these pregnancies. This review explores the problematic issue of antenatal DS screening in assisted conception pregnancies. For the singletons and twins, a sequential NT and second-trimester serum marker screening can be offered, thus producing a single risk estimation which seems to be more accurate. For the high order of multiplicity, the NT offers additional important data, which can be taken in consideration both as a screening tool for DS and if fetal reduction is planned.
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PMID:Antenatal screening for Down's syndrome in assisted reproductive pregnancies. 1058 90

Human chorionic gonadotropin (hCG) is the hormone of pregnancy and forms the basis of all pregnancy tests as well as diagnostic assays for a variety of pathological states including certain types of cancers and some diseases of pregnancy and genetic abnormalities. In recent years, the discovery of the diagnostic utility of measurement of the free subunits and fragments of the hormone, especially in urine, has proven of special use for diagnosis of very early pregnancy loss, an important phenomenon related to infertility, as well as part of screening programs for Down Syndrome and gynecological cancers. This article summarizes existing and new methods for the preparation of hCG, its subunits, and the beta core fragment from urinary sources. The methods for proper analyses of these materials are also described to enable investigators to prepare and analyze these materials in various quantities in their own laboratories.
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PMID:Preparation and analysis of the common urinary forms of human chorionic gonadotropin. 1076 3


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