Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An attempt was made to elucidate the association between retinopathy of prematurity (ROP) and neurological disorders in infants of very low birth weight. In this retrospective study, 1081 Japanese children weighing less than 1500 g at birth were classified into four subgroups according to birth weight. In each subgroup, the association among cerebral palsy (CP) or mental retardation (MR) and ROP, treated ROP, and cicatricial ROP was analyzed statistically. In the population as a whole, CP and MR were positively associated with ROP. However, in the birth weight subgroup analysis, no significant association was found. We can conclude that there is a weak association between ROP and CP or MR.
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PMID:Weak association between retinopathy of prematurity and neurological disorders in childhood. 958 48

Medical problems associated with prematurity are frequently complex, and a multidisciplinary approach is often required. Some common problems include the following: (1) anemia, which can be reduced by iron supplementation, (2) cerebral palsy or mental retardation as a result of intraventricular hemorrhage or periventricular leukomalacia, (3) respiratory problems, including bronchopulmonary dysplasia and apnea, (4) visual problems, such as those associated with retinopathy of prematurity, (5) gastroesophageal reflux and (6) surgical problems, including inguinal or umbilical hernia and cryptorchidism. Monitoring of growth and development includes recording the infant's head circumference, weight and length on a growth chart for premature infants. Nutritional status should be assessed at each visit, watching for hyperosmolar problems in infants receiving high-calorie formulas. Consultation with other specialists may be required if abnormalities are identified during follow-up care in the office.
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PMID:Office care of the premature infant: Part II. Common medical and surgical problems. 961 10

Regular ophthalmic surveillance started in 1982 for all surviving prematures in Frederiksborg County considered at risk of developing retinopathy of prematurity (ROP). During 1982-1984 185 infants of gestational age 25-35 weeks at delivery were examined; blindness eventually appeared in four out of the 28 who showed some stage of ROP. All 28 attended ophthalmic reassessment at age 7-10 years and were compared with 60 of the same cohort without evidence of ROP. At follow-up (n = 88) there was evidence of psychomotor disturbances in 45 children, manifesting as major CNS damage in 21, and minor in 24. With correction for drop-outs the regional frequency of severe CNS damage (mainly cerebral palsy and mental retardation) was 29.6% for gestational ages < 32 weeks at delivery and 24% as calculated for birth weights < 1500 g. An analysis of perinatal factors based mainly on matched pairs did not indicate any definite association with subsequent damage to eye or brain, and statistically there was no association between severity of ROP and CNS impairment. We have no explanation for the high frequency of CNS impairment at follow-up.
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PMID:[Brain damage in relation to occurrence of retinopathy of prematurity. A regional ophthalmologic follow up of premature infants born 1982-1984]. 964 Oct 57

Norrie disease (ND) is a severe form of congenital blindness accompanied by mental retardation and/or deafness in at least one third of the patients. This article summarizes advances in the molecular genetic analysis of this disease during the last 13 years, including mapping and cloning of the human gene and the generation and characterization of a mouse model. Genetic linkage studies and physical mapping strategies have assigned the ND locus to the proximal short arm of the human X chromosome. The identification of chromosomal rearrangements in several patients, such as microdeletions, enabled the isolation of the ND gene by a positional cloning approach. Numerous point mutations in this gene have been identified in three distinct clinical entities: (1) ND, (2) familial and sporadic exudative vitreoretinopathy, and (3) retinopathy of prematurity. The gene encodes a relatively small protein, consisting of 133 amino acids. The function of the gene product is yet unknown, although homologies with known proteins and molecular modelling data suggest a role in the regulation of cell interaction or differentiation processes. A mouse model has been generated to shed more light on early pathogenic events involved in ND and allelic disorders. The mouse homologous protein is highly identical (94%) to the human polypeptide. The gene is expressed in the neuronal layers of the mouse retina, the cerebellum and olfactory epithelium. Mutant mice show snowflake-like opacities within the vitreous, dysgenesis of the ganglion cell layer and occasionally degeneration of photoreceptor cells. The mouse phenotype does not include phthisis bulbi and, overall, resembles a mild form of ND. Electrophysiological studies revealed a severely altered electroretinogram b-wave. These results suggest a primary defect in the inner neuronal layers of the retina. Defects in the vitreous and photoreceptor cell layer are most likely secondary effects. Further histological, functional and molecular studies of the mouse model are needed to provide additional information on disease associated pathways.
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PMID:Molecular dissection of Norrie disease. 983 55

To get a comprehensive picture of prematurity and neonatal death or survival, all factors on the maternal and fetal records that might be pertinent were recorded. This information, having to do with factors such as age, gravida of the mother, blood group incompatibility, period of gestation, weight at birth, type of delivery, medication and anesthesia administered to the mother, is presented in tabular form. In the study of perinatal mortality it was noted that failure to establish normal pulmonary ventilation is the most common cause of death in the neonatal period. Maternal history of relative infertility, that is, previous abortions, stillbirths and premature deliveries, was the most impressive finding in the stillborn series. In the follow-up study of premature infants who survived the neonatal period, 8.5 per cent were found to be severely handicapped. In four cases the handicap was due to congenital anomalies, in two others probably to infection, leaving 12 with complications possibly ascribable to prematurity. Six of these had retrolental fibroplasia as a major handicap. In seven, mental retardation was the presenting problem. Most of the handicapped children had multiple handicaps, which included spasticity, delayed motor development, strabismus, etc. The incidence of the necessity for corrective measures for feet and legs appeared relatively high. In general, survivors compared favorably with the rest of the childhood population. Complications and twinning were associated inordinately often.
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PMID:A five-year study of prematurity. 1330 92

Fifteen years of evidence have established that the cytokine erythropoietin offers promise as a treatment for brain injury. In particular, neonatal brain injury may be reduced or prevented by early treatment with recombinant erythropoietin. Extreme prematurity and perinatal asphyxia are common conditions associated with poor neurodevelopmental outcomes including cerebral palsy, mental retardation, hearing or visual impairment, and attention deficit hyperactivity disorder. When high doses of erythropoietin are administered systemically, a small proportion crosses the blood-brain barrier and can protect against hypoxic-ischemic brain injury. In addition to other protective effects, erythropoietin can specifically protect dopaminergic neurons. Since reduced dopamine neurotransmission contributes to attention deficit hyperactivity disorder, this condition may be amenable to erythropoietin treatment. This review focuses on the potential application of erythropoietin as a neuroprotectant with regard to neurologic complications of extreme prematurity, including attention deficit hyperactivity disorder. Recent concerns that early erythropoietin might exacerbate the pathologic neovascularization associated with retinopathy of prematurity are addressed.
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PMID:Recent trends in erythropoietin-mediated neuroprotection. 1793 39

X-linked Norrie disease, familial exudative vitreoretinopathy (FEVR), Coat's disease and retinopathy of prematurity are severe human eye diseases and can all be caused by mutations in the Norrie disease pseudoglioma gene. They all show vascular defects and characteristic features of retinal hypoxia. Only Norrie disease displays additional neurological symptoms, which are sensorineural hearing loss and mental retardation. In the present study, we analysed transcript levels of the ligand Norrin (Ndph) and its two receptors Frizzled-4 (Fzd4) and LDL-related protein receptor 5 (Lrp5) in six different brain regions (cerebellum, cortex, hippocampus, olfactory bulb, pituitary and brain stem) of 6- to 8-month-old wild-type and Ndph knockout mice by quantitative real-time PCR. No effect of the Ndph knockout allele on Fzd4 or Lrp5 receptor expression was found. Furthermore, no alterations of the transcript levels of three hypoxia-regulated angiogenic factors (Vegfa, Itgrb3 and Tie1) were observed in the absence of Norrin. Interestingly, we identified significant differences in Ndph, Fzd4 and Lrp5 transcript levels in brain regions of wild-type mice and observed highest expression of Norrin and frizzled-4 in cerebellum. Transcript analyses were correlated with morphological data obtained from cerebellum and immunohistochemical studies of blood vessels in different brain regions. Vessel density was reduced in the cerebellum of Ndph knockout mice but the number of Purkinje and granular cells was not altered. This provides the first description of a brain phenotype in Ndph knockout mice, which will help to elucidate the role of Norrin in the brain.
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PMID:Vascular changes in the cerebellum of Norrin /Ndph knockout mice correlate with high expression of Norrin and Frizzled-4. 1854 47


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