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)

West syndrome is an age-specific epileptic syndrome with onset in infancy. It comprises infantile spasms (usually flexion convulsions), EEG pattern of hypsarrhythmia and mental retardation. Current therapy involves ACTH, corticosteroids, valproic acid, pyridoxine and vigabatrine. The treatment is difficult and more effective antiepileptic drugs are required. Unfortunately, there is no animal model of West syndrome that would accurately depict the situation found in humans. N-methyl-D-asparate (NMDA)-induced seizures in infant rats have certain features of the West syndrome model. These seizures are age-specific (they occur before 25 days of age), include hyperflection (emprosthotonus), their EEG is not specific and they somewhat respond to treatment with the benzodiazepine clonazepam. In 12 and 18 day old rats, we tested the effects of hydrocortisone, pyridoxine and sodium valproate against the seizures induced by 15 and 45 mg/kg of NMDA i.p., respectively. There were weak effects of sodium valproate against the NMDA-induced emprosthotonus. In contrast, high doses of pyridoxine were proconvulsant and hydrocortisone worsened the damage of nerve cells induced by NMDA. The data show that NMDA-induced seizures although similar to West syndrome are extremely resistant to therapy and may not be a good model of the West syndrome. However, the search for an adequate model that would allow for determination of possible mechanisms and testing of putative antiepileptic drugs will continue.
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PMID:West syndrome model: seek and you will find. 960 4

We reported a 24-year-old woman with moderate mental retardation and partial epilepsy. She developed complex partial seizures at 3 years of age and generalized tonic convulsions at 9 years. Chromosome analysis revealed that she had mosaicism (87%) of 46, XX, and r(20) (p13,q13.3). Her electroencephalogram showed bilateral 2-3 Hz sharp and wave complex over the bilateral frontopolar, and centro-parieto-occipital areas. Computed tomographic and magnetic resonance image examinations were normal. Twenty-five cases of ring 20 chromosome karyotypes (including this case) have been reported in the literature; 19 showed epilepsy, and 18 showed moderate mental retardation. Many of the patients showed growth retardation and minor malformations. The ring 20 syndrome is associated with a high incidence of epilepsy, particularly partial epilepsy. Our findings indicate that the main features of the ring 20 syndrome are partial epilepsy and mental retardation.
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PMID:A study of ring 20 chromosome karyotype with epilepsy. 968 35

The main objectives of this study were to characterize the selected variables for a better understanding and diagnosis of infantile autism such as clinical and image findings, diagnostic criteria, frequency of neuropsychiatric disorders in the subjects' families, familial recurrence and occurrence of consangunity between the subjects' parents and between other couples in the family. The sample was composed of 36 subjects of both sexes, in the age group from 1 though 20 years old, members of 35 distinctive families, all of which presenting clinical diagnosis for infantile autism. Mental retardation was clinically observed in all subjects of the sample and convulsion in 27.8%; neuropsychiatric disorders were referred in at least one family member of the subjects (97.14% of the families); recurrent autism in 11.42% grandparents and great-grand-parents (2.86%); abnormal findings in computed tomography scan were observed in three subjects. These results support the suggestion of the multifactorial heredity model with differential threshold fold sex in infantile autism. The clinical evaluation of all infantile autism cases should always appraise the neurological, psychiatric and genetic features.
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PMID:[Genetic and clinical diagnosis of infantile autism]. 968 16

Variegate porphyria (VP) is a low penetrance, autosomal dominant disorder that results from partial deficiency of protoporphyrinogen oxidase (PPOX) activity caused by mutation in the PPOX gene. The rare homozygous variant of VP is characterized by severe PPOX deficiency, onset of photosensitization by porphyrins in early childhood, skeletal abnormalities of the hand and, less constantly, short stature, mental retardation and convulsions. We have identified PPOX mutations on both alleles of five of the 11 unrelated patients with homozygous VP reported to date. Two patients were homoallelic for missense mutations (D349A and A433P), while three were heteroallelic. Functional analysis by prokaryotic expression showed that the D349A and A433P and one missense mutation in each of the three heteroallelic patients (G358R in two patients and A219KANA) preserved some PPOX activity (9.5-25% of wild-type). Mutations on the other allele of the heteroallelic patients abolished or markedly decreased activity. There was no relation between genotype assessed by functional analysis and the presence or severity of non-cutaneous manifestations. The mutations were absent from 104 unrelated patients with autosomal dominant VP. Our findings define the molecular pathology of homozygous VP and suggest that mild PPOX mutations occur in the general population but have very low or no clinical penetrance in heterozygotes.
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PMID:Molecular characterization of homozygous variegate porphyria. 981 36

The term Baller-Gerold syndrome was coined by Cohen [1979: Birth Defects 15(5B): 13-63] to designate the phenotype of craniosynostosis and radial aplasia. It is thought to be a rare autosomal recessive condition, which, in some patients, presents with additional abnormalities, such as polymicrogyria, mental retardation or anal atresia. A phenotypic overlap of Baller-Gerold and Roberts-SC phocomelia syndrome was noted when a patient with bicoronal synostosis and bilateral radial hypoplasia was found to have premature centromere separation, a finding characteristic of Roberts syndrome [Huson et al.,1990: J Med Genet 27:371-375]. Other cases of presumed Baller-Gerold syndrome were rediagnosed as Fanconi pancytopenia, Rothmund-Thomson syndrome or VACTERL association. These reports led to a narrowed redefinition of Baller-Gerold syndrome based on the exclusion of cytogenetic and hematopoetic abnormalities and the absence of additional malformations in patients with craniosynostosis and preaxial upper limb abnormalities. Here we report on a patient with unilateral radial aplasia and bicoronal synostosis without additional malformations and without chromosome breakage, who fits this narrow definition of Baller-Gerold syndrome. We identified a novel TWIST gene mutation in this patient, a Glu181Stop mutation predicting a premature termination of the protein carboxy-terminal to the helix 2 domain. This report provides further evidence that Baller-Gerold is of heterogeneous cause, and a thorough evaluation is indicated to identify a possibly more specific diagnosis, including Saethre-Chotzen syndrome. This differential diagnosis is of particular importance, as it is an autosomal dominant trait. Therefore, the recurrence risk for parents of an affected child can be 50% if one parent carries the mutation, as opposed to the 25% recurrence risk for autosomal recessive inheritance. Offspring of the affected patient also have a 50% risk to inherit the mutation, while the risk to bear an affected offspring for an autosomal recessive trait is very low.
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PMID:TWIST gene mutation in a patient with radial aplasia and craniosynostosis: further evidence for heterogeneity of Baller-Gerold syndrome. 993 84

We report on a family with an X linked neurodegenerative disorder consisting of mental retardation, blindness, convulsions, spasticity, and early death. Neuropathological examination showed mild hypomyelination. By linkage analysis, the underlying genetic defect could be assigned to the pericentromeric region of the X chromosome with a maximum lod score of 3.30 at theta=0.0 for the DXS1204 locus with DXS337 and PGK1P1 as flanking markers.
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PMID:A new X linked neurodegenerative syndrome with mental retardation, blindness, convulsions, spasticity, mild hypomyelination, and early death maps to the pericentromeric region. 1005 Oct 14

Whether the combined diagnosis of cerebral palsy with mental retardation or with mental retardation and epilepsy reflects more severe manifestations of the spectrum of cerebral palsy, or whether these conditions reflect overlapping outcomes related to different exposure, remains an open question. At two centers, in Rome and Conegliano, Italy, 51 children with combined cerebral palsy, mental retardation, and epilepsy, 31 children with both cerebral palsy and mental retardation, and 48 with cerebral palsy alone were identified and examined, and their mothers interviewed. The triple diagnosis group was significantly more likely than the other two groups to have a history of neonatal convulsions and a history of epilepsy in first-degree relatives, but less likely to have a mother's age at delivery greater than 33 years, a birthweight less than 1500 g, or gestational age less than 32 weeks. The dual diagnosis group was more likely than the other two groups to have maternal education of less than 8 years. These data suggest the possibility of different etiopathogenetic pathways for various presentations of cerebral palsy.
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PMID:Differing risk factors for cerebral palsy in the presence of mental retardation and epilepsy. 1019 Feb 64

Angelman syndrome (AS) is a neurological disorder with a heterogeneous genetic aetiology. It most frequently results from a de novo interstitial deletion in the 15q11-q13 region, but in a few cases it is caused by paternal uniparental disomy (UPD) or an imprinting mutation. The remaining 20 to 30% of AS patients exhibit biparental inheritance and a normal pattern of allelic methylation in the 15q11-q13 region. In this latter group, mutations in the UBE3A gene have recently been shown to be a cause of AS. Here we describe the phenotypic expression in 14 AS cases involving eight UBE3A mutations. These comprise 11 familial cases from five families and three sporadic cases. Subtle differences from the typical phenotype of AS were found. Consistent manifestations were psychomotor delay, a happy disposition, a hyperexcitable personality, EEG abnormalities, and mental retardation with severe speech impairment. The other main manifestations of AS, ataxia, epilepsy, and microcephaly, were either milder or absent in various combinations among the patients. In addition, myoclonus of cortical origin was frequently observed with severe fits inducing myoclonic seizures. The majority of the patients were overweight. This study showed that ataxia, myoclonus, EEG abnormalities, speech impairment, characteristic behavioural phenotype, and abnormal head circumference are attributable to a deficiency in the maternally inherited UBE3A allele. Furthermore, analysis of mutation transmission showed an unexpectedly high rate of somatic mosaicism in normal carriers. These data have important consequences for genetic counselling.
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PMID:Angelman syndrome resulting from UBE3A mutations in 14 patients from eight families: clinical manifestations and genetic counselling. 1042 18

We report on the association of a gastric carcinoma and a constitutional deletion of the short arm of chromosome 18 in a 14-year-old patient. The phenotype of the patient, including microcephaly, ptosis, micrognathia, tetralogy of Fallot, and mental retardation, fits well with previously reported cases of del(18p); she also showed a positive serology against Helicobacter pylori. The comparison of the alleles of polymorphic loci located on the short arm of chromosome 18 between the patient and her parents showed a maternal origin of the abnormal chromosome. Loss of heterozygosity (LOH) for loci located in the long arm of chromosome 18 is a frequent event in gastric carcinomas; it was observed in the tumoral mass of our patient and again, the alleles lost were of maternal origin. We postulate that the constitutional chromosomal abnormality may have favored the loss of the abnormal chromosome in some cells and that the loss of the deleted chromosome 18 (demonstrated by LOH for this chromosome in the tumoral mass) has been an early step in the pathogenesis of the gastric carcinoma of our patient with Helicobacter pylori infection acting as a cofactor.
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PMID:Early onset of gastric carcinoma and constitutional deletion of 18p. 1045 56

Nonconvulsive status epilepticus (NCSE) is much more common than is generally appreciated and is certainly underdiagnosed, but its long-term effects are largely undetermined and remain controversial. There is increasing experimental evidence that generalized convulsive status epilepticus produces lasting neuropathologic damage in the hippocampus, but experimental models often include provocation of status epilepticus (SE) by physical (e.g., electrical stimulation) and chemical (including excitotoxic) agents that may induce damage independent of the epileptiform discharges. Also, damage appears to be related to the intensity and duration of electrical stimulation. Such models usually include high-frequency discharges sustained over long periods, somewhat different from the electrical activity of typical human NCSE. Pathologic studies in humans pertain primarily to patients who have had generalized convulsive status epilepticus. Clinical studies of the effects of NCSE are mandatory, but conclusions are difficult to come by, in part because of diverse definitions of NCSE. An altered mental status is obligatory, but the pertinent EEG and medication response criteria are controversial. Response to medication can be delayed by many hours or even days. Absence SE appears to cause no lasting effects. Complex partial SE is less uniform. Most reported cases have returned to baseline neurologic function, but several well-described patients have had prolonged memory deficits. The significance of other deficits is difficult to interpret in light of concomitant vascular and other diseases causing neurologic dysfunction. Clinical series usually lack premorbid neurologic and neuropsychologic assessment. The few exceptions are complicated by preexisting mental retardation and other deficits, by the coexistence of progressive illness, by the later effects of recurrent seizures, and almost always by the confounding influence of anticonvulsant medications. Most morbidity appears attributable to the underlying illnesses rather than to the NCSE itself. It is possible that relatively infrequent cases of prolonged NCSE or those with the synergistic effect of concomitant systemic illness, focal lesions, or very rapid excitatory epileptiform discharges may suffer more long-lasting damage, but these observations are still preliminary. NCSE should be treated expeditiously because of the acute neurologic impairment of the patients, because of the attendant morbidity including physical injury, and because it may go on to generalized convulsions. There is reasonable concern about possible long-term effects, but permanent neurologic damage from NCSE has not yet been established as a mandate for urgent treatment.
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PMID:Evidence against permanent neurologic damage from nonconvulsive status epilepticus. 1047 5


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