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Query: UMLS:C0917816 (mental retardation)
 15,867 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A Consensus Conference utilizing available literature and expert opinion sponsored by the American College of Medical Genetics in October 1995 evaluated the rational approach to the individual with mental retardation. Although no uniform protocol replaces individual clinician judgement, the consensus recommendations were as follows: 1. The individual with mental retardation, the family, and medical care providers benefit from a focused clinical and laboratory evaluation aimed at establishing causation and in providing counseling, prognosis, recurrence risks, and guidelines for management. 2. Essential elements of the evaluation include a three-generation pedigree: pre-, peri-, and post-natal history, complete physical examination focused on the presence of minor anomalies, neurologic examination, and assessment of the behavioral phenotype. 3. Selective laboratory testing should, in most patients, include a banded karyotype. Fragile X testing should be strongly considered in both males and females with unexplained mental retardation, especially in the presence of a positive family history, a consistent physical and behavioral phenotype and absence of major structural abnormalities. Metabolic testing should be initialed in the presence of suggestive clinical and physical findings. Neuroimaging should be considered in patients without a known diagnosis especially in the presence of neurologic symptoms, cranial contour abnormalities, microcephaly, or macrocephaly. In most situations MRI is the testing modality of choice. 4. Sequential evaluation of the patient, occasionally over several years, is often necessary for diagnosis, allowing for delineation of the physical and behavioral phenotype, a logical approach to ancillary testing and appropriate prognostic and reproductive counseling.
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PMID:Evaluation of mental retardation: recommendations of a Consensus Conference: American College of Medical Genetics. 937 33

We report the case of a 41 year-old woman with a slight mental retardation and epilepsy. MRI showed a diffuse subependymal heterotopia. The cognitive level supports the view that the ectopic cells are probably not important for the normal cortical functions but that they are likely able to maintain some of the electric properties of normal neurons, even if with altered discharge modalities. The genetic etiology of subependymal neuronal migration disorders is discussed. This is the second reported case of diffuse subependymal heterotopia in a female patient.
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PMID:Case report: subependymal diffuse heterotopia. Clinical, EEG, and neuroimaging findings. 939 23

We examined the clinical picture of eight patients with severe intellectual and motor disabilities, who had experienced prolonged and severe neonatal jaundice, and showed localized lesions in the globus pallidus, subthalamic nuclei and hippocampus on MRI. All patients had athetoid tetraplegia, and five patients showed disturbed ocular movements and seven showed dysphagia. Five patients could communicate with others or utter words, and all showed mental retardation. Auditory brainstem responses were abnormal in seven, and the percentage of REM sleep on all-night polysomnography was reduced in three. Neither CT nor T1-weighted MR images could detect any changes in the pallidum or subthalamic nuclei, while T2-weighted MR images disclosed bilateral high signals in the pallidum, especially in the internal segment, in all patients. Five of the 7 patients, in whom coronal T2-weighted MR imagings were obtained, showed high signals in the subthalamic nuclei. The hippocampus showed atrophy and/or T2-prolongation in seven patients. In one autopsy case, these MRI changes were concordant with pathological lesions. In patients with athetoid cerebral palsy, brainstem dysfunctions, and abnormal ABR, localization of MRI lesions to the pallidum and subthalamic nuclei is evidence for neonatal bilirubin encephalopathy.
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PMID:[Localized lesions on MRI in the globus pallidus, subthalamic nuclei and hippocampus in patients with severe intellectual and motor disabilities]. 939 98

We report an autopsy case of bathtub drowning in epilepsy. A 26-year-old female with mental retardation had been treated for refractory epilepsy. Her younger sister found her floating supine in the bathtub 45 min after starting bathing. Neuropathological examination revealed cerebral cortical dysplasia in the precentral gyrus of the left hemisphere, which had not been detected by MRI, suggesting the etiology of epilepsy. In bathtub submersion injury of an unidentified cause, neuropathological examination should be performed to reveal any lesion underlying epileptic seizures. Additionally, we present statistics on bathtub submersion injury in children aged 5 years or older in Japan based upon nationwide survey data obtained in 1991. Forty-seven percent of them had associated epilepsy or convulsive attacks and 71% died. It is necessary for epileptic patients and their families to understand that the risk of bathtub drowning can be minimized if proper precautions are taken.
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PMID:An autopsy case of bathtub drowning in epilepsy. 940

The clinical and radiological features of a patient with Cutis Verticis Gyrata-Mental Deficiency syndrome are reported. The clinical features of the patient included severe mental retardation, drug resistant epilepsy, short stature, microcephaly with multiple furrows on the scalp and normally growing overlying hair. He was blind with bilateral optic atrophy, multiple joint contractures and spastic tetraplegia. Skull X-ray showed thickened calvarial bones but other features of pachydermoperiostosis were absent. Brain MRI showed well developed, albeit small, frontal and anterior temporal lobes with a normal gray-white matter interface. The parietal and occipital cortex were atrophic with widening of the occipital horns (colpocephaly). The sylvian fissures were accentuated because of atrophic parietal operculae. The splenium of the corpus callosum was hypoplastic. There was atrophy of the cerebellar cortex. Contrary to the previously described cerebral cortical polymicrogyria in Cutis Verticis Gyrata-Mental Deficiency syndrome, there was no evidence to suggest any migration disorder in our patient. The present report highlights the clinico-radiological heterogeneity of the syndrome.
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PMID:Cutis verticis gyrata-mental deficiency syndrome: report of a case with unusual neuroradiological findings. 957 Dec 85

The somatosensory evoked potentials in two children with a unilateral migration disorder (pachygyria) of the cerebrum, which was detected by MRI, were examined in order to evaluate the function of the malformed sensory cortex. A 5-year-old girl had slight left hemiparesis, seizures, and mental retardation, and a 4-month-old boy had left hemiparesis. Neither patient showed distinct sensory disturbance. Short latency somatosensory evoked potentials and somatosensory evoked potentials recordings demonstrated that the early cortical component, N20, was absent and a positive wave appeared on paretic left-hand stimulation. On nonparetic right-hand stimulation, the primary evoked response (N20-P30) of the left hemisphere, which originates in Broadmann area 3b, was almost normal. Multichannel recordings on the scalp of one patient revealed that a positive wave without polarity inversion appeared posterior to the right central sulcus on median nerve stimulation on the paretic side. The radial dipole in the sensory cortex (area 1 or area 3a) or motor cortex (area 4) could have formed the positive/negative biphasic wave in the relatively wide centroparietal area in the present patients. In the case of unilateral cortical dysplasia, the malformed cortex with subnormal function of sensation might induce the change in the early component of somatosensory evoked potentials.
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PMID:Somatosensory evoked potentials with a unilateral migration disorder of the cerebrum. 962 11

Nonsyndromic X-linked mental retardation (MRX) syndromes are clinically homogeneous but genetically heterogeneous disorders, whose genetic bases are largely unknown. Affected individuals in a multiplex pedigree with MRX (MRX30), previously mapped to Xq22, show a point mutation in the PAK3 (p21-activated kinase) gene, which encodes a serine-threonine kinase. PAK proteins are crucial effectors linking Rho GTPases to cytoskeletal reorganization and to nuclear signalling. The mutation produces premature termination, disrupting kinase function. MRI analysis showed no gross defects in brain development. Immunofluorescence analysis showed that PAK3 protein is highly expressed in postmitotic neurons of the developing and postnatal cerebral cortex and hippocampus. Signal transduction through Rho GTPases and PAK3 may be critical for human cognitive function.
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PMID:PAK3 mutation in nonsyndromic X-linked mental retardation. 973 25

Neuronal migration anomalies are a spectrum of brain malformations caused by insults to migrating neuroblasts during the sixth week to fifth month of gestation. To study the characteristics of MRI findings in migration anomalies, MR images of 36 patients (28 children and 8 adults) with migration anomalies were evaluated. Five patients had lissencephaly, eight had pachygyria, twelve had schizencephaly, six had heterotopias of gray matter, three had hemimegalencephaly, and two had polymicrogyria. The frequency of migration anomalies was 0.51% of all cranial MRI studies and 1.21% of pediatric cranial MRI studies at our hospital. The major clinical presentations of these patients were seizure (64%), development delay (42%), motor deficits (42%) and mental retardation (25%). Twenty-five patients (69%) associated with other brain anomalies, including: other migration anomalies in 12 cases (33%), absence of the septum pellucidum in 10 cases (28%), Dandy-Walker malformation/variant in 5 cases, arachnoid cyst in 4 cases, agenesis of the corpus callosum in 3 cases, holoprosencephaly in 2 cases, mega cisterna magna in 1 case and cephalocele in 1 case. Some of them presented with multiple complicated anomalies. As MR imaging provides superb gray-white matter distinction, details of cortical anatomy and multiplanar capability, it can clearly delineate the detail morphologic changes of the brain caused by neuronal migration disorders as well as the associated anomalies.
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PMID:Magnetic resonance images of neuronal migration anomalies. 978 Jun 1

Non-specific X-linked mental retardation is a heterogeneous group of disorders with an incidence of approximately 1 in 500 males. A recently identified gene in Xq12, encoding a Rho-GTPase-activating protein, was found to be mutated in individuals with mental retardation. We describe here two sisters with a 46,XY karyotype and a microdeletion of the oligophrenin-1 gene and 1.1 Mb of flanking DNA. We have characterised the molecular interval defining this microdeletion syndrome with the fibre-FISH technique. A visual physical map of 1.2 Mb was constructed which spans the oligophrenin-1 gene and the androgen receptor gene. The analysis of the patients revealed a deletion which extended from the 5' end of the AR gene to a region approximately 80 kb proximal to the EPLG2 gene. The clinical manifestations of the two sisters include psychomotor retardation, seizures, ataxia, hypotonia and complete androgen insensitivity. Cranial MRI scans show enlargement of the cerebral ventricles and cerebellar hypoplasia. Our findings give further support for the involvement of the oligophrenin-1 gene in specific morphological abnormalities of the brain which is of importance in the investigation of male patients presenting with mental retardation. In combination with our results from physical mapping we suggest that a region around the oligophrenin-1 locus is relatively bereft of vital genes.
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PMID:Deletion including the oligophrenin-1 gene associated with enlarged cerebral ventricles, cerebellar hypoplasia, seizures and ataxia. 1043 59

Deficiency of cystathionine beta-synthase (CBS) is the commonest cause of primary homocystinuria. Homocysteine metabolism is intimately linked with the metabolism of folate, vitamin B12 (cobalamin) and pyridoxine. It is hypothesised that the pathogenesis of neuropsychiatric manifestations in homocystinuria, folate and cobalamin deficiencies are related to imbalance neurotransmitters in the CNS through disturbances in the pathways linking the metabolism of homocysteine and these vitamins. Although neuropsychiatric disorders are relatively common among patients with homocystinuria, it is not well recognised as the causative factor among patients presenting with neuropsychiatric disorders. A 31 year old woman presented with a three week history of delirium and inappropriate and labile affect. There was no history suggestive of drug or alcohol abuse, nutritional deficiency or organic disorders. EEG, cerebral CT, MRI and microbiological investigations did not reveal any organic causes. Because of a diagnosis of pyridoxine-responsive homocystinuria seven years previously, the possibility of homocystinuria was considered and investigated. Laboratory tests revealed macrocytosis and a high concentration of urinary total homocystine. Commencement of pyridoxine at 400 mg/day resulted in disappearance of homocystine in urine within four days with remarkable clinical improvement. Homocystinuria should be considered in the differential diagnosis of unexplained neuropsychiatric disorders in patients who have past or family history of homocystinuria, mental retardation, thromboembolic episodes, vascular diseases or clinical and laboratory features resembling folate and/or vitamin B12 deficiencies. Homocystinuria-associated neuropsychiatric disturbances can easily be treated with pyridoxine in 50% of cases.
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PMID:Homocystinuria and psychiatric disorder: a case report. 1050 67


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