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

In general, carriers of paracentric inversions are phenotypically normal, although individual reports describe like occurrence of infertility, miscarriages and mental retardation in inversion carriers. We present a family with paracentric inversion of 1p [karyotype: 46,XY/XY, inv(1)(p13.2p36.2)] in 7 of the 12 investigated family members. The index patient, a four year-old boy was referred for motor and mental retardation. The possible relationship between the paracentric inversion and the MR/MCA syndrome in the index patient of this family is briefly discussed.
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PMID:Paracentric inversion in the short arm of chromosome 1. Report of a family and review of the literature. 1473 16

Complex chromosomal rearrangements (CCRs) are usually associated with infertility or subfertility in male carriers. If fertility is maintained, there is a high risk of abnormal pregnancy outcome. Few male carriers have been identified by children presenting with mental retardation/congenital malformations (MR/CM) or by spontaneous abortions of the spouses. We report a de novo CCR with five breakpoints involving chromosomes 4, 10 and 14 in a male carrier who was ascertained through a son presenting with MR/CM due to an unbalanced karyotype with partial trisomy 14 and partial monosomy 4. The child has a healthy elder brother. In the family history no abortions were reported. No fertility treatment was necessary. Cytogenetic analysis from the affected son showed a reciprocal translocation t(4;10) with additional chromosomal material inserted between the translocation junctions in the derivative chromosome 10. The father showed the same derivative chromosome 10 but had additionally one aberrant chromosome 14. Further molecular cytogenetic analyses determined the inserted material in the aberrant chromosome 10 as derived from chromosome 14 and revealed a small translocation with material of chromosome 4 inserted into the derivative chromosome 14. Thus the phenotype of the son is supposed to be associated with a partial duplication 14q13-->q24.1 and a partial monosomy 4q27-->q28. Including our case we are aware of eleven CCR cases with fertile male carriers. In eight of these families normal offspring have been reported. We propose that exceptional CCRs in fertile male carriers might form comparatively simple pachytene configurations increasing the chance of healthy offspring.
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PMID:A complex chromosomal rearrangement with a translocation 4;10;14 in a fertile male carrier: ascertainment through an offspring with partial trisomy 14q13-->q24.1 and partial monosomy 4q27-->q28 [corrected]. 1500 58

Knowledge of the human genome has opened the genomic era. The genome instability, its causes and the possible consequences especially about fertility start to be understood. This instability can be observed on chromosome structure but also on genes. Different chromosomes rearrangements involved in infertility including translocations and Y chromosome deletions are described. The Y chromosome is a model of instability, and this instability is the source of its evolution. All those rearrangements are the results of illegitimate recombinations between homologous sequences. On genes we find punctual and dynamic mutations, polymorphisms and epigenetic abnormalities. They all are the results of ADN replication mistakes not corrected by the cellular machine. This machinery is the guardian of the genome integrity and in case of abnormality the programmed cellular death is induced. The knowledge of all these instability mechanisms is essential to appreciate the risk for the offspring after intracytoplasmic sperm injection. Indeed we go round physiological barriers without a complete understanding of the mechanisms involved. Thus, this is an important challenge for research teams but also for all assisted reproduction centers, dealing with ART. Genome is unstable - the very basis of its evolution. But this is also the cause of mistakes with pathological consequences like infertility and mental retardation.
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PMID:[Genomic instability and male infertility]. 1558 77

VATER "association" is a common condition, with the diagnosis typically based on a characteristic constellation of congenital anomalies. Reported long-term follow-up information on VATER association is limited, thus making it difficult to prognosticate the future of infants and children with this condition. Further, there are few data on how often the initial diagnosis of VATER association is correct. Some information has been published on growth deficiency and mental retardation, but these data are minimal [Bull et al., 1985; Mapstone et al., 1986; Weaver et al., 1986] and for the most part look at children under the age of 10 years. We have undertaken a long-term follow-up of individuals with VATER association originally reported by Weaver et al. [1986] or diagnosed with VATER association by his associates and him after 1986. Out of the 50 patients, we were able to contact 20 individuals or families. Two of the 20 individuals had died: 1 at 3 days with cardiac failure due to a truncus arteriosus, and 1 at 4 years of unspecified cause. Two were unwilling to participate. Of the rest, we interviewed and examined seven persons, and interviewed another nine by telephone. Of the 16, 5 had some degree of cognitive impairment. These individuals were more likely to have congenital anomalies outside of the typical scope of VATER association, such as prune belly sequence or findings of CHARGE association. Of the nine individuals with a history of imperforate anus, five had partial or complete incontinence as adults leading to difficulties in maintaining employment. Height was at the 5th centile or less in 6 of 16 patients. Three of four patients who were trying to have children, had infertility. In two women, the infertility was thought to be related to congenital anomalies of the genitourinary system and multiple pelvic operations. We also present the long-term medical and neurologic problems in these individuals.
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PMID:Adults with VATER association: long-term prognosis. 1615 41

The objective of the present study was to determine the frequency of somatic chromosomal anomalies and Y chromosomal microdeletions (azoospermia factor genes, AZF) in infertile males who seek assisted reproduction. These studies are very important because the assisted reproduction techniques (mainly intracytoplasmic sperm injection) bypass the natural selection process and some classical chromosomal abnormalities, microdeletions of AZF genes or some deleterious genic mutations could pass through generations. These genetic abnormalities can cause in the offspring of these patients male infertility, ambiguous external genitalia, mental retardation, and other birth defects. We studied 165 infertile men whose infertility was attributable to testicular problems (60 were azoospermic, 100 were oligospermic and 5 were asthenospermic). We studied 100 metaphases per patient with GTG banding obtained from temporary lymphocyte culture for chromosomal abnormality detection and performed a genomic DNA analysis using 28 Y chromosome-specific sequence-tagged sites for Y AZF microdeletion detection. Karyotyping revealed somatic anomalies in 16 subjects (16/165 = 9.6%). Of these 16, 12 were in the azoospermic group (12/60 = 20%) and 4 were in the oligospermic group (4/100 = 4%). The most common chromosomal anomaly was Klinefelter syndrome (10/165 = 6%). Microdeletions of AZF genes were detected in 12 subjects (12/160 = 7.5%). The frequencies detected are similar to those described previously. These results show the importance of genetic evaluation of infertile males prior to assisted reproduction. Such evaluation can lead to genetic counseling and, consequently, to primary and secondary prevention of mental retardation and birth defects.
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PMID:Somatic cytogenetic and azoospermia factor gene microdeletion studies in infertile men. 1661 80

The endocannabinoid system, including its receptors (CB(1) and CB(2)), endogenous ligands ('endocannabinoids'), synthesising and degrading enzymes, as well as transporter molecules, has been detected from the earliest stages of embryonic development and throughout pre- and postnatal development. In addition, the endocannabinoids, notably 2-arachidonyl glycerol, are also present in maternal milk. During three distinct developmental stages (i.e. embryonic implantation, prenatal brain development and postnatal suckling), the endocannabinoid system appears to play an essential role for development and survival. Thus, during early pregnancy, successful embryonic passage through the oviduct and implantation into the uterus both require critical enzymatic control of optimal anandamide levels at the appropriate times and sites. During foetal life, the cannabinoid CB(1) receptor plays a major role in brain development, regulating neural progenitor differentiation into neurones and glia and guiding axonal migration and synaptogenesis. Postnatally, CB(1) receptor blockade interferes with the initiation of milk suckling in mouse pups, by inducing oral motor weakness, which exposes a critical role for CB(1) receptors in the initiation of milk suckling by neonates, possibly by interfering with innervation of the tongue muscles. Manipulating the endocannabinoid system by pre- and/or postnatal administration of cannabinoids or maternal marijuana consumption, has significant, yet subtle effects on the offspring. Thus, alterations in the dopamine, GABA and endocannabinoid systems have been reported while enhanced drug seeking behaviour and impaired executive (prefrontal cortical) function have also been observed. The relatively mild nature of the disruptive effects of prenatal cannabinoids may be understood in the framework of the intricate timing requirements and frequently biphasic effects of the (endo)cannabinoids. In conclusion, the endocannabinoid system plays several key roles in pre- and postnatal development. Future studies should further clarify the mechanisms involved and provide a better understanding of the adverse effects of prenatal exposure, in order to design strategies for the treatment of conditions such as infertility, mental retardation and failure-to-thrive.
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PMID:Multiple roles for the endocannabinoid system during the earliest stages of life: pre- and postnatal development. 1842 4

The Hyderabad Metropolitan Area had 562 lakes at one time, but only 162 now remain. These are polluted to various degrees and pose environmental and health hazards. The Hussain Sagar Lake provided water for irrigation and drinking until 1930 and supported aquatic life till 1976. It is now contaminated by organic chemicals discharged by many industrial estates in its basin. An estimated 28,190 cmum of industrial effluents and domestic sewage are let into it daily. Phenols, benzenes, cyanides, and toxic metals make it poisonous. The ground water around the lake is also polluted. The polluted lakes ruin vegetable farms, kill fetuses in the womb, and cause mental retardation, still births, and infertility. In the city's outskirts, clinically confirmed cancer is 11 times higher and heart ailments 16 times more than elsewhere. The Hyderabad Urban Development Authority (HUDA) took up a Lake Conservation and Restoration Project as part of its Green Environment Program in 2002. Several lakes have been restored by setting up effluent (or sewage) treatment plants. HUDA also built lake parks with recreation facilities and environment education centers. HUDA also organized jointly with the World Water Institute, Pune, India, an international workshop on urban lake conservation and management in June 2003. It adopted the Hyderabad Declaration which, among other things, states the worthy aim of restoring all the water bodies by 2009. Even if it takes a few more years, the restoration of all the polluted lakes will usher in multiple benefits to Hyderabad citizens.
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PMID:From poison ponds to pleasure spots. 1899 11

The FXTAS syndrome (Fragile X-associated tremor/ataxia syndrome) is a specific neurodegenerative syndrome affecting subjects carrying a premutation of the FMR1 (fragile X mental retardation 1) gene. It affects mainly men with the premutation and aged more than 50 years. This syndrome is separate and distinct from the fragile X syndrome. The FXTAS syndrome remains underestimated today. It should be considered in patients older than 50 years with tremors and cerebellar ataxia, especially when Parkinson disease or cognitive disorders are present or when there is a family history of infertility, early menopause, or mental retardation. In these patients, hyperintense signals of mid-cerebellar peduncle images on T2 and FLAIR MRI justify genetic testing for the FMR1 premutation.
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PMID:[Tremor/ataxia syndrome related to Fragile X premutation]. 1941 33

In meiosis I, homologous chromosomes become paired and then separate from one another to opposite poles of the spindle. In humans, errors in this process are a leading cause of birth defects, mental retardation, and infertility. In most organisms, crossing-over, or exchange, between the homologous partners provides a link that promotes their proper, bipolar, attachment to the spindle. Attachment of both partners to the same pole can sometimes be corrected during a delay that is triggered by the spindle checkpoint. Studies of non-exchange chromosomes have shown that centromere pairing serves as an alternative to exchange by orienting the centromeres for proper microtubule attachment. Here, we demonstrate a new role for the synaptonemal complex protein Zip1. Zip1 localizes to the centromeres of non-exchange chromosomes in pachytene and mediates centromere pairing and segregation of the partners at meiosis I. Exchange chromosomes were also found to experience Zip1-dependent pairing at their centromeres. Zip1 was found to persist at centromeres, after synaptonemal complex disassembly, remaining there until microtubule attachment. Disruption of this centromere pairing, in spindle checkpoint mutants, randomized the segregation of exchange chromosomes. These results demonstrate that Zip1-mediated pairing of exchange chromosome centromeres promotes an initial, bipolar attachment of microtubules. This activity of Zip1 lessens the load on the spindle checkpoint, greatly reducing the chance that the cell will exit the checkpoint delay with an improperly oriented chromosome pair. Thus exchange, the spindle checkpoint, and centromere pairing are complementary mechanisms that ensure the proper segregation of homologous partners at meiosis I.
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PMID:The synaptonemal complex protein Zip1 promotes bi-orientation of centromeres at meiosis I. 2001 Nov 12

It is often assumed that current disability constructs exist in conceptual isolation from one another. This article explores the tangled historical relationship between "mental retardation" and learning disability in the writings and speeches of special education pioneer Samuel A. Kirk. Beginning in the 1950s, Kirk repeatedly told an educability narrative that described children with low IQ scores as capable students worthy of instruction. However, when he tried to clearly distinguish between the new learning disability construct and the older mental retardation, Kirk altered his standard tale. True intellectual potential then shifted to the learning disability, leaving mental retardation doubly stigmatized as the disorder of educational infertility.
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PMID:Turning the educability narrative: Samuel A. Kirk at the intersection of learning disability and "mental retardation". 2144 74


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