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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In man, the period of maximum risk for the embryo and foetus is between the second and tenth week after conception. The most frequent and most severe malformation is microcephaly which in extreme cases is accompanied by mental retardation. The results of studies in experimental animals and man agree that it is impossible to demonstrate any increased risk of malformation with doses below 15 rads, and that the increase over the spontaneous incidence of malformation is slight at doses below 25 rads. A very small increase in the frequency of leukaemias and cancers has been observed after irradiation in utero for pelvimetry, which delivers a few rads; it can be estimated from these data that a dose of 2 rads induces at the most the risk of one case of cancer in 2,000 children. In practice, it is only exceptionally that an abortion is advised after a diagnostic radiological examination, since the doses in these circumstances are relatively low. A therapeutic termination of pregnancy should be advised when the dose is greater than 20 rads, but it is necessary to take into account other medico-social factors. Conversely, it is important to avoid any irradiation in women who could be pregnant and in particular avoid any irradiation of the true pelvis during the 10 days prior to menses and especially if there has been a delay in the start of menstruation. In pregnant women radiological examinations should only be made if they are of paramount importance for the mother, and all precautions taken to reduce the dose to the uterus in the absolute minimum.
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PMID:[The problems raised by the irradiation of pregnant women. Effects of ionizing radiations on the embryon and foetus (author's transl)]. 11 30

A female infant presented with absent vagina and uterus, absent left kidney, absent right gonad, growth failure, mental retardation, seizure disorder, and facial, limb, and hand anomalies. The chromosome karyotype was 46, XY in her blood and cultured cells, including cells from the sites of both gonads. Her H-Y antigen was positive. Specific dihydrotestosterone binding was reduced in cells from a labial skin biopsy. The case might be due to a minute deletion of the short arm of the X chromosome, resulting in loss of a gene for androgen receptors and of adjacent chromosomal material responsible for the growth failure and the somatic and neurologic anomalies.
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PMID:Incomplete testicular feminization with multiple congenital abnormalities. 61 83

A female child, born at term to a mother who contracted varicella in early pregnancy, presented with multiple congenital defects. These included mental retardation, numerous skeletal anomalies, and absent uterus and vagina. Urologic anomalies included bilateral chronic pyelonephritis secondary to vesicoureteric reflux. This pattern of congenital abnormalities has not been reported previously.
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PMID:Congenital varicella syndrome with genitourinary anomalies. 96 Mar 47

In a retrospective cohort study of 47 Wilms' tumor survivors and their 77 sibling controls, female survivors had a fourfold excess risk (risk ratio, 4.1; 95% confidence interval, 1.7-10.1) for any adverse livebirth outcome, including birth defects, compared with their sibling controls. Wives of male survivors had no apparent excess risk for problem pregnancies. The families had a number of severe reproductive problems and major birth defects, such as primary amenorrhea in two survivors, bicornuate uterus in two survivors and one control, and mental retardation in one male survivor and a male control. The son of a female survivor died after bilateral Wilms' tumors. Birth defects in the offspring of female survivors are compatible either with intrauterine constraint, possibly due to radiation-induced fibrosis or with the complex of malformations associated with Wilms' tumor. Female survivors of Wilms' tumor appear to be at increased risk for a variety of reproductive problems, from sterility to fetal loss, early delivery, and birth defects in offspring. Furthermore, relatives of survivors of Wilms' tumor may be at risk of having associated birth defects, with clinically significant consequences.
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PMID:Reproductive problems and birth defects in survivors of Wilms' tumor and their relatives. 284 33

Radiation doses absorbed by the uterus, ovary, testicle and active bone marrow are computed for cervical, thoracic, lumbar, full spine and chest series performed under typical office conditions. Assuming a nonthreshold, linear relationship between dose and radiogenic effect, the computed tissue-specific doses are used to estimate the probability that each X-ray series might enhance the statistical probability of occurrence of an adult leukemia fatality of the irradiated patient; a childhood leukemia, mental retardation or cancer fatality as a result of fetal irradiation; or a variety of sex cell chromosomal aberrations in irradiated patients. It is concluded that the greatest hazard to active bone marrow, the uterus and the gonads is posed by lumbar and full spine radiography and that the need to adequately justify such exposure is mandatory; furthermore, in these series, irradiation of the ovary is 10 times as great as that of the testicle. Lumbar radiographic examinations can be made significantly safer by the elimination of the lumbosacral spot view.
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PMID:Organ-specific dosimetry in spinal radiography: an analysis of genetic and somatic effects. 335 98

If the mother is the fragile X gene carrier, her daughters (and sons) with the mutation are at high risk of mental retardation. If the father is the (clinically unaffected) carrier, his daughters are normal. This is strong evidence for a maternal effect. The decreased penetrance and variable expressivity in fra(X) offspring of carriers could be related, at least in part, to variabile expression or availability of some maternal factor between pregnancies. We hypothesize a maternal effect in fra(X), with variability in intelligence of heterozygotes and hemizygotes mediated mainly by the maternal uterus or placenta by virtue of different patterns of lyonization in those tissues between pregnancies. If the mother is a carrier, the maternal placenta could develop with a skewed proportion of the normal or the fra(X) genetically active. Each female or male embryo could be exposed to very different environments with respect to genetic activity of the fra(X) chromosome, depending on the site of implantation within the uterus. If the father contributes the fra(X), the intrauterine environment is invariably normal and so are the daughters. Modifiers of the intrauterine effect could include lyonization patterns in tissues of the carrier fetus, and preferential inactivation of the paternal X in extra-embryonic tissues. The ultimate phenotype of the developing heterozygote and hemizygote may be determined by a threshold effect and interaction between the maternal genotype, the placental genotype, and the fetal genotype. The possibility of maternal effect is testable and has implications for treatment.
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PMID:Maternal effect on intelligence in fragile X males and females. 351 74

An abnormal extra band on the short arm of the X chromosome was found in a 7-year-old reared as a female, of mixed gonadal dysgenesis. She had ambiguous external genitalia, scoliosis, short stature, mental retardation and motor paralysis of the limbs. Chromosomal analysis revealed the karyotype of 46,Xp+ Y. An uterus with fallopian tube, a streak gonad on the left side and a testicle on the right side were discovered at exploratory laparotomy. Bilateral gonads and fallopian tube were removed. The chromosomal analysis of her normal mother showed the presence of the same abnormal X chromosome (46, X Xp+). In the literature, we found some cases of intersexuality with Xp+ in karyotype. The relationship between our own case and these Xp+ cases was discussed briefly. Thirty-five cases of mixed gonadal dysgenesis have been reported in Japanese literature, our own case being the 36th case.
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PMID:[A case of mixed gonadal dysgenesis with structural abnormalities of X chromosome (Xp+)]. 406 Dec 20

A 23-year-old phenotypic female with congenital heart disease, mental retardation and mild virilization was referred for evaluation of short stature and delayed sexual development. Endocrine studies revealed a markedly elevated serum testosterone, which was within the adult range. At laparotomy, a small uterus, normal fallopian tubes and bilateral gonadal tumors, consisting of a left gonadoblastoma and right dysgerminoma were found. Trypsin G banding of peripheral blood revealed a 45,XO, 18p+ karyotype. Q banding demonstrated intense fluorescence of the distal portion of the extra material on chromosome 18, consistent with fluorescence of Y chromosomal heterochromatin. A combination of banding techniques enabled us to determine a 45,X,t(Y;18) (p11;p11) karyotype in peripheral blood. Cultures of gonadal tissue revealed 45,X,t(Y;18)/46,XY mosaicism.
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PMID:Cytogenetic and endocrine findings in a female with 45,X,t(y;18) (p11;p11). 719 97

The prognosis of mortality of four or more fetuses in the same pregnancy is put at 20% in the perinatal period, and another 20% within the first year of life. In addition, the higher number of fetuses faces a 50% risk of impairment, and quintuplets face a 90% risk of mental retardation. In 1988 in the New England Journal of Medicine, a discussion on reducing the number of several fetuses was published. In 1989 the reduction by means feticide was made public by the German Federal Chamber of Physicians eliciting ongoing controversy. From 1984 to 1992 there had been 67 cases of multiple fetuses, and in 43 cases selective feticide was performed in the Department of Prenatal Diagnosis of the Bonn University Gynecology Clinic. The first selective feticide technique in France, in 1982, consisted of vaginal aspiration out of the uterus. Later came transabdominal operations with aspiration of the amniotic fluid and puncture of the fetal heart, or injecting filtered air into the navel vein, or, later, potassium chloride into the heart of the fetus by means of a fetoscope, a technique later abandoned as too risky. In the case of a twin pregnancy resulting from in vitro fertilization, one was cornual pregnancy, and selective feticide saved the mother a major abdominal operation which probably would have resulted in the loss of both fetuses. The risks of selective feticide include infection and consequent miscarriage, and a 10% risk that the wrong fetus is killed and the sick fetus survives (only two such cases have been reported). However, the differentiation of the afflicted fetus from the healthy one is feasible by ultrasound in almost all cases. Recent statistics from England and Wales indicate a drop in abortions for fetal indication to 2000 in the past 10 years.
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PMID:[Fetocide in multiple pregnancy]. 830 25

Preimplantation genetic diagnosis was performed in 61 day 3 embryos obtained by in-vitro fertilization from seven patient carriers of haemophilia, Marfan's syndrome, Bloch-Sulzemberg syndrome (incontinentia pigmentosa) or X chromosome-linked immune deficiency, retinitis pigmentosa, and FG syndrome, which is characterized by mental retardation and hypotonia. After multiplex polymerase chain reaction, 16 embryos were diagnosed as being unaffected, and these were transferred to the uterus on the following day (day 4). Of these embryos, six (37.5%) implanted, resulting in the delivery of a singleton and a twin pregnancy, a late second trimester miscarriage (twins at week 20) and a first trimester miscarriage at week 8. All the diagnoses were confirmed by amniocentesis. We report for the first time a late day 4 transfer of biopsied human embryos undergoing preimplantation genetic diagnosis. This transfer schedule allows an extra day to perform genetic analyses on single blastomeres and to monitor any adverse effect of the biopsy procedure.
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PMID:Successful outcome with day 4 embryo transfer after preimplantation diagnosis for genetically transmitted diseases. 968 8


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