Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A receptor mapping technique using iodine-123 iomazenil and single-photon emission tomography (SPET) was employed to examine benzodiazepine receptor binding in a patient with Angelman syndrome (AS). AS is characterized by developmental delay, seizures, inappropriate laughter and ataxic movement. In this entity there is a cytogenic deletion of the proximal long arm of chromosome 15q11-q13, where the gene encoding the GABAA receptor beta3 subunit (GABRB3) is located. Since the benzodiazepine receptor is constructed as a receptor-ionophore complex that contains the GABAA receptor, it is a suitable marker for GABA-ergic synapsis. To determine whether benzodiazepine receptor density, which indirectly indicates changes in GABAA receptor density, is altered in the brain in patients with AS, we investigated a 27-year-old woman with AS using 123I-iomazenil and SPET. Receptor density was quantitatively assessed by measuring the binding potential using a simplified method. Regional cerebral blood flow was also measured with N-isopropyl-p-[123I]iodoamphetamine. We demonstrated that benzodiazepine receptor density is severely decreased in the cerebellum, and mildly decreased in the frontal and temporal cortices and basal ganglia, a result which is considered to indicate decreased GABAA receptor density in these regions. Although the deletion of GABRB3 was not observed in the present study, we indirectly demonstrated the disturbance of inhibitory neurotransmission mediated by the GABAA receptor in the investigated patient. 123I-iomazenil with SPET was useful to map benzodiazepine receptors, which indicate GABAA receptor distribution and their density.
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PMID:Decrease in benzodiazepine receptor binding in a patient with Angelman syndrome detected by iodine-123 iomazenil and single-photon emission tomography. 869 70

We report on a mentally retarded boy with epileptic seizures, microcephaly, ataxia, and developmental delay. His clinical features were consistent with Angelman syndrome. Fluorescent in situ hybridization and DNA analysis showed a deletion of chromosome 15 q11-13 and thus confirmed the diagnosis. In addition, the patient had a unilateral, incomplete cleft lip, a feature which has not previously been reported in Angelman syndrome.
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PMID:Unilateral cleft lip in a boy with Angelman syndrome. 877 3

Angelman syndrome (AS), characterized by mental retardation, seizures, frequent smiling and laughter, and abnormal gait, is one of the best examples of human disease in which genetic imprinting plays a role. In about 70% of cases, AS is caused by de novo maternal deletions at 15q11-q13 (ref. 2). Approximately 2% of AS cases are caused by paternal uniparental disomy (UPD) of chromosome 15 (ref. 3) and 2-3% are caused by "imprinting mutations'. In the remaining 25% of AS cases, no deletion, uniparental disomy (UPD), or methylation abnormality is detectable, and these cases, unlike deletions or UPD, can be familial. These cases are likely to result from mutations in a gene that is expressed either exclusively or preferentially from the maternal chromosome 15. We have found that a 15q inversion inherited by an AS child from her normal mother disrupts the 5' end of the UBE3A (E6-AP) gene, the product of which functions in protein ubiquitination. We have looked for novel UBE3A mutations in nondeletion/non-UPD/non-imprinting mutation (NDUI) AS patients and have found one patient who is heterozygous for a 5-bp de novo tandem duplication. We have also found in two brothers a heterozygous mutation, an A to G transition that creates a new 3' splice junction 7 bp upstream from the normal splice junction. Both mutations are predicted to cause a frameshift and premature termination of translation. Our results demonstrate that UBE3A mutations are one cause of AS and indicate a possible abnormality in ubiquitin-mediated protein degradation during brain development in this disease.
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PMID:UBE3A/E6-AP mutations cause Angelman syndrome. 898 71

The diagnosis of Angelman syndrome has seldom been made in infancy because the typical craniofacial dysmorphism and the typical outbursts of unprovoked laughter are not fully developed before the second and third year of life. Other features such as mental retardation or absence of language, though invariably present, are less obvious in the first year of life. We describe three children in whom consecutive electroencephalographic (EEG) studies show very large amplitude slow activity at 2-3/s, often rhythmic, usually occurring in prolonged runs and often more prominent posteriorly, sometimes with spikes or sharp-wave activity, and invariably associated with a diffuse rhythmic activity at 4-6/ s of 200 microvolts. The changes were present as early as six months of life. They preceded development of seizure and occurred much earlier than the craniofacial dysmorphology. It is concluded that methodical use of EEG in the elucidation of children with developmental disorder and knowledge of the characteristic EEG picture may help to identify patients with Angelman syndrome at an early age and before the clinical features become obvious.
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PMID:[EEG and early diagnosis of Angelman syndrome]. 907 74

We studied the clinical and EEG-findings in 28 adult patients (aged 20-53 years) with Angelman syndrome (AS). Twenty-three showed a maternal chromosome 15q11-13 deletion; in 5, the diagnosis was based on a combination of typical clinical findings. Compared to the clinical manifestations present in childhood, "coarsening" of facial traits (100%), thoracic scoliosis (71%), and being wheelchair-bound (39%) were found more frequently. Paroxysms of laughter were still observed in adulthood (79%), but less frequently than in childhood. Most adult patients could feed themselves, but needed help with many daily activities. The majority (82%) had epileptic seizures. Abnormal EEG-activity consisting of 2-3/s rhythmic triphasic waves of high amplitude with a maximum over the frontal regions, which has been identified in many AS children, was found in 67% of these adult patients.
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PMID:Angelman syndrome in adulthood. 907 12

Angelman's syndrome is a rare genetic disorder characterized by developmental delay, craniofacial abnormalities, ataxia, paroxysmal laughter, and seizures. The diagnosis is suspected in infants who have the characteristic clinical features and electroencephalographic (EEG) abnormalities and is confirmed by the genetic identification of a maternally derived 15q11-13 deletion. We report on 3 patients with genetically confirmed Angelman's syndrome who had the characteristic clinical and EEG features. The EEGs demonstrated high-amplitude 2- to 3-Hz delta activity, with intermittent spike-and-slow-wave discharges maximal in the occipital region in 2 patients and generalized sharp-and-slow-wave discharges, occipital spikes, and electrographic status epilepticus during slow-wave sleep in the other patient. The findings of generalized high-amplitude delta slowing and occipital spike-and-wave discharges, facilitated by eye closure, in children with developmental delay and seizures suggest the diagnosis of Angelman's syndrome and should lead to genetic testing.
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PMID:Angelman's syndrome: clinical and electroencephalographic findings. 914 90

Angelman syndrome (AS) is a human genetic disorder characterized by mental retardation, seizures, inappropriate laughter, abnormal galt, tremor and ataxia. There is strong genetic evidence that the disorder is associated with a maternally expressed, imprinted gene mapping to chromosome 15q11-13. Affected patients demonstrate varied molecular abnormalities, including large maternal deletions, uniparental paternal disomy (UPD). Imprinting mutations and loss of function mutations of E6-associated-protein (E6-AP) ubiquitin-protein ligase (UBE3A). All of these abnormalities are associated with loss of maternal expression of UBE3A. Although mutations in UBE3A cause AS, indicating that maternal-specific expression of UBE3A is essential for a normal phenotype, evidence for maternal-specific expression of UBE3A has been lacking. Using mice with partial paternal UPD encompassing Ube3a to differentiate maternal and paternal expression, we found by in situ hybridization that expression of Ube3a in Purkinje cells, hippocampal neurons and mitral cells of the olfactory bulb in UPD mice was markedly reduced compared to non-UPD littermates. In contrast, expression of Ube3a in other regions of the brain was only moderately or not at all reduced in UPD mice. The major phenotypic features of AS correlate with the loss of maternal-specific expression of Ube3a in hippocampus and cerebellum as revealed in the mouse model.
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PMID:Imprinted expression of the murine Angelman syndrome gene, Ube3a, in hippocampal and Purkinje neurons. 928 1

We compared epilepsy phenotypes with genotypes of Angelman syndrome (AS), including chromosome 15q11-13 deletions (class I), uniparental disomy (class II), methylation imprinting abnormalities (class III), and mutation in the UBE3A gene (class IV). Twenty patients were prospectively selected based on clinical cytogenetic and molecular diagnosis of AS. All patients had 6 to 72 hours of closed-circuit television videotaping and digitized electroencephalogrpahic (EEG) telemetry. Patients from all genotypic classes had characteristic EEGs with diffuse bifrontally dominant high-amplitude 1- to 3-Hz notched or triphasic or polyphasic slow waves, or slow and sharp waves. Class I patients had severe intractable epilepsy, most frequently with atypical absences and myoclonias and less frequently with generalized extensor tonic seizures or flexor spasms. Epileptic spasms were recorded in AS patients as old as 41 years. Aged-matched class II, III, and IV patients had either no epilepsy or drug-responsive mild epilepsy with relatively infrequent atypical absences, myoclonias, or atonic seizures. In conclusion, maternally inherited chromosome 15q11-13 deletions produce severe epilepsy. Loss-of-function UBE3A mutations, uniparental disomy, or methylation imprint abnormalities in AS are associated with relatively mild epilepsy. Involvement of other genes in the chromosome 15q11-13 deletion, such as GABRB3, may explain severe epilepsy in AS.
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PMID:Angelman syndrome: correlations between epilepsy phenotypes and genotypes. 954 30

Deficiency of methylenetetrahydrofolate reductase (MTHFR) is associated with a variable phenotype that includes mental retardation, gait abnormalities, and seizures. Many of the same clinical findings are also seen in patients with Angelman syndrome. We report on a patient with MTHFR deficiency who was initially diagnosed as having Angelman syndrome. This case illustrates that MTHFR deficiency can mimic the phenotype of Angelman syndrome and that MTHFR deficiency should be excluded in patients with manifestations of Angelman syndrome whose molecular studies of chromosome 15 are normal.
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PMID:Methylenetetrahydrofolate reductase deficiency in a patient with phenotypic findings of Angelman syndrome. 960 86

The authors describe the case of a typical Angelman syndrome patient. The proband presents developmental delay, mental retardation, macrostomia, wide-spaced teeth, seizures, absent speech, jerky gait, and paroxysms of laughter. The cytogenetic and molecular studies showed a maternal deletion of 15q11q13. These results are in agreement with the clinical diagnosis of Angelman syndrome.
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PMID:[Angelman syndrome: a frequently undiagnosed cause of mental retardation and epilepsy. Case report]. 962 97


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