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)

The Aberrant Behavior Checklist was used to collect data from a large United States institution for comparison with ratings previously obtained in New Zealand. A total of 531 subjects within the American facility and 937 residents of New Zealand institutions were studied. The United States data were factor analyzed using the same procedures that were employed to develop the scale in New Zealand. In addition, subscales of the Checklist were analyzed as a function of sex, age, country, and level of mental retardation. Finally, the effects of various medical conditions were analyzed. The original factor structure of the Checklist was validated for the United States sample, with a mean coefficient of congruence of .93 averaged across the five factors. Sex failed to influence subscale scores, whereas age, country, and severity of retardation significantly affected ratings. Deafness was unrelated to Checklist scores whereas cerebral palsy, epilepsy, psychosis, and psychoactive drug treatment were related.
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PMID:The aberrant behavior checklist: factor structure and the effect of subject variables in American and New Zealand facilities. 359 45

The clinical findings in 11 families with 52 members affected with the Waardenburg syndrome (WS) are presented and compared with the findings from other studies. The families are assigned to WS type I (7 families containing 31 affected individuals), or type II (4 families with 21 affected members), depending on the presence or absence of dystopia canthorum, and the differences between the two types are discussed. The hypothesis that the features of WS are explicable on the basis of a neural crest defect is supported. Attention is drawn to the finding of spina bifida in 2 unrelated WS type I patients, and of delayed milestones or poor school performance necessitating special schooling in 9 different unrelated patients. Deafness has previously been considered to be the most disabling characteristic of the condition, but if there is an increased incidence of spina bifida or mental retardation associated with WS, the approach to genetic counselling might need to be altered.
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PMID:Waardenburg syndrome in South Africa. Part I. An evaluation of the clinical findings in 11 families. 646 2

Hypophosphatasia (HPP) is a bone metabolic disorder caused by mutations in the liver/bone/kidney alkaline phosphatase gene (ALPL), which encodes tissue-nonspecific alkaline phosphatase (TNAP). This disease is characterized by disrupted bone and tooth mineralization, and reduced serum AP activity. Along with bone and tooth symptoms, many neurological symptoms, seizure, encephalopathy, intracranial hypertension, mental retardation, deafness, and growth hormone deficiency (GHD), are frequently found in HPP patients. Seizure occurs in severe HPP types soon after birth, and responds to pyridoxine, but is an indicator of lethal prognosis. Encephalopathy rarely presents in severe HPP types, but has severe sequelae. Intracranial hypertension complicated in mild HPP types develops after the age of 1 year and sometimes need neurosurgical intervention. Mental retardation, deafness and GHD are more frequently found in Japanese HPP patients. Mental retardation occurs in all HPP types. Deafness in perinatal lethal type is both conductive and sensorineural. GHD develops in all but perinatal lethal type and the diagnosis tends to delay. The pathogenesis of these neural features of HPP might be due to impairment of both vitamin B6 metabolism and central nervous system development by ALPL mutations.
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PMID:Neurological Symptoms of Hypophosphatasia. 2621 17

Mutations in TBC1D24 are described in patients with a spectrum of neurological diseases, including mild and severe epilepsies and complex syndromic phenotypes such as Deafness, Onycodystrophy, Osteodystrophy, Mental Retardation and Seizure (DOORS) syndrome. The product of TBC1D24 is a multifunctional protein involved in neuronal development, regulation of synaptic vesicle trafficking, and protection from oxidative stress. Although pathogenic mutations in TBC1D24 span the entire coding sequence, no clear genotype/phenotype correlations have emerged. However most patients bearing predicted loss of function mutations exhibit a severe neurodevelopmental disorder. Aim of the study is to investigate the impact of TBC1D24 knockdown during the first stages of neuronal differentiation when axonal specification and outgrowth take place. In rat cortical primary neurons silenced for TBC1D24, we found defects in axonal specification, the maturation of axonal initial segment and action potential firing. The axonal phenotype was accompanied by an impairment of endocytosis at the growth cone and an altered activation of the TBC1D24 molecular partner ADP ribosylation factor 6. Accordingly, acute knockdown of TBC1D24 in cerebrocortical neurons in vivo analogously impairs callosal projections. The axonal defect was also investigated in human induced pluripotent stem cell-derived neurons from patients carrying TBC1D24 mutations. Reprogrammed neurons from a patient with severe developmental encephalopathy show significant axon formation defect that were absent from reprogrammed neurons of a patient with mild early onset epilepsy. Our data reveal that alterations of membrane trafficking at the growth cone induced by TBC1D24 loss of function cause axonal and excitability defects. The axonal phenotype correlates with the disease severity and highlight an important role for TBC1D24 in connectivity during brain development.
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PMID:TBC1D24 regulates axonal outgrowth and membrane trafficking at the growth cone in rodent and human neurons. 3085 6