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)

We determined the diagnostic value of the EEG in young children with Angelman syndrome (AS) and Rett syndrome (RS). EEGs, recorded before 5 years of age, of 10 patients with AS, 10 with RS and 10 with mental retardation of other origin were studied blindly by two examiners for the presence of the following items: (A) 4-6 Hz rhythmic activity of over 200 microV; (B) 2-3 Hz frontal activity of 200-500 microV; (C) posterior spikes; (D) triphasic frontal waves; (E) central and/or centro-temporal spike-wave complexes; and (F) other epileptic discharges. Based on these items the EEGs were scored as AS (A-D); RS (E-F); or other. Examiners never made a mistake between AS and RS. One examiner labeled 6 of 10 AS cases correctly, the other 5; 4 (5) were characterized as 'other.' In RS cases 5 were labeled as 'other' by the first examiner and 3 by the second one. We conclude that EEG patterns of AS and RS are sufficiently different to help differentiate between AS and RS at a young age, which has a bearing on genetic counseling.
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PMID:The diagnostic value of the EEG in Angelman and Rett syndrome at a young age. 968 Jan 52

Formerly thought to be a neurodegenerative disease, Rett syndrome (RS) is a neurodevelopmental arrest of the brain that almost exclusively affects females and occurs in a variety of racial and ethnic groups worldwide. RS begins in late infancy and is characterized by autistic and dementia-like behavior, ataxia, and purposeless hand movements. Its cause and mode of transmission are unknown in over 90% of cases; however, there is strong and convincing evidence that genetic factors play a major role. The reported incidence varies, but in the US, as many as one quarter to one third of female children in mental wards/institutions may be affected. RS has been mistaken for numerous other conditions, including autism, cerebral palsy, and mental retardation, but the clinical picture is unique: No other condition has a period of rapid deterioration followed by apparent stabilization or even improvement in autistic features, eye contact, seizure activity, and hand stereotypies. The diagnosis is supported by deceleration of head growth, evidence of neurologic regression with associated neurologic signs, and purposeless hand stereotypies, with a clinical history of developmental regression. The differential diagnosis often involves ruling out syndromes with similar signs of neurodevelopmental arrest--for example, meningitis or encephalitis; chromosomal disorders such as Angelman's syndrome and Prader-Willi syndrome; metabolic disorders such as ornithine carbamoyltransferase deficiency; disorders of organic acids and amino acids; neurovisceral storage diseases; mitochondrial cytopathy; and Batten disease, or infantile neuronal ceroid lipofuscinosis. Management encompasses a comprehensive medical, therapeutic, educational, and psychosocial approach, best provided through a team in collaboration with the community agencies that serve families and children with special needs.
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PMID:Understanding, Recognizing, and Treating Rett Syndrome. 974 85

We report on an interstitial duplication of the long arm of chromosome 11 [46XX,dup(11) (q23.3)] in a girl with atypical Rett syndrome (RS). This case was discovered during a systematic cytogenetic study of RS. Fluorescent in situ hybridization including total chromosome painting and use of regional specific YAC, cosmid and plasmid probes, was used to confirm the chromosome 11q involvement and to identify the landmarks of the smallest 11q duplication reported to date. The findings are compared to cases of trisomy 11q reported previously, all of which have a larger duplication and different clinical manifestations. Surprisingly, mental retardation and behavior disorders are less severe in these cases.
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PMID:Identification and molecular characterization of a small 11q23.3 de novo duplication in a patient with Rett syndrome manifestations. 984 53

We describe a 6 1/2-year-old girl with an interstitial deletion of chromosome arm 18q (18q21.1q22.3). Her clinical manifestations are a combination of those found in monosomy 18q syndrome and those of Rett syndrome. Cytogenetic analysis demonstrated a deletion of the long arm of chromosome 18, defined by molecular analysis with polymorphic markers as a de novo interstitial deletion, paternally derived. The findings typical of the 18q- syndrome included mental retardation, midface hypoplasia, and hypoplasia of labia majora, and those typical of Rett syndrome were severe mental retardation, autistic behavior, inappropriate hand-washing movements, epilepsy, attacks of sighing and hyperventilation, and progressive scoliosis since the age of 5 years. She did not have microcephaly, and the mental delay was obvious from an early age without a period of normal development, which makes the diagnosis of Rett syndrome atypical. Previously, a girl with mosaicism for a monosomy 18q associated with Rett syndrome has been described. That girl had a terminal deletion of chromosome 18q, which seems to coincide in part with that in the present girl. It is possible that genes in the distal region of 18q are involved in the etiology of Rett syndrome.
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PMID:Monosomy 18q syndrome and atypical Rett syndrome in a girl with an interstitial deletion (18)(q21.1q22.3). 1005 Nov 71

Rett syndrome is a unique and puzzling disorder noted in females and is possibly caused by fundamental failures in critical brain connectivity during early infancy. The most frequent habits in Rett syndrome are hand sucking or biting, bruxism and mouth breathing. Children with musculoskeletal disorders and children who suffer from mental retardation commonly grind their teeth. A five year old female case with Rett syndrome is presented with significant bruxism in this article.
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PMID:Bruxism in Rett syndrome: a case report. 1020 60

Mutation of FMR1 results in fragile X mental retardation. The most common FMR1 mutation is expansion of a CGG repeat tract at the 5' end of FMR1, which leads to cytosine methylation and transcriptional silencing. Both DNA methylation and histone deacetylation have been associated with transcriptional inactivity. The finding that the methyl cytosine-binding protein MeCP2 binds to histone deacetylases and represses transcription in vivo supports a model in which MeCP2 recruits histone deacetylases to methylated DNA, resulting in histone deacetylation, chromatin condensation and transcriptional silencing. Here we demonstrate that the 5' end of FMR1 is associated with acetylated histones H3 and H4 in cells from normal individuals, but acetylation is reduced in cells from fragile X patients. Treatment of fragile X cells with 5-aza-2'-deoxycytidine (5-aza-dC) resulted in reassociation of acetylated histones H3 and H4 with FMR1 and transcriptional reactivation, whereas treatment with trichostatin A (TSA) led to almost complete acetylated histone H4 and little acetylated histone H3 reassociation with FMR1, as well as no detectable transcription. Our results represent the first description of loss of histone acetylation at a specific locus in human disease, and advance understanding of the mechanism of FMR1 transcriptional silencing.
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PMID:Acetylated histones are associated with FMR1 in normal but not fragile X-syndrome cells. 1031 71

Entorhinal cortex (EC), fascia dentata (FD), hippocampus (HP), and basal ganglia (BG) were studied in Rett syndrome (RS) cases and compared with control brains and an autism case. Kluver-Barrera and Golgi methods were used. In RS most of the areas of EC, HP, and FD showed severe cell hypochromia. In the EC all cells of layer II and most in layer III were in a state of total chromatolysis or were "ghost" cells, but the cells of layers V and VI were preserved and moderately hyperchromic. In FD and HP the majority of the granular cells and cells of CA3 and CA4 fields were severely hypochromic, whereas in the CA1 field most cells were normal or slightly hypercaryochromic. In BG mostly mild or moderate aberration from normal cell structure was observed: in striatum, mild hypercaryochromia of small neurons and more expressive hyperchromia of large neurons were found; and in pallidum, mild or moderate hypercaryochromia to severe hyperchromia in pallidum internum was found. Degeneration of thick myelinated fibers was evident in pallidum. Large striatal and pallidal neurons showed signs of constructive changes in Golgi slices. These data allow the determination of the cause of the main symptoms of RS. The motor disorders, including specific stereotyped movements, could be related to the enhanced activity of BG cells due to their deafferentation from the side of the neocortex and to supposed hyperactivity of the EC-striatal pathway; the mental retardation and epileptic seizures could be due to FD-HP involvement.
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PMID:Morphological study of the entorhinal cortex, hippocampal formation, and basal ganglia in Rett syndrome patients. 1034 23

Rett syndrome (RTT, MIM 312750) is a progressive neurodevelopmental disorder and one of the most common causes of mental retardation in females, with an incidence of 1 in 10,000-15,000 (ref. 2). Patients with classic RTT appear to develop normally until 6-18 months of age, then gradually lose speech and purposeful hand use, and develop microcephaly, seizures, autism, ataxia, intermittent hyperventilation and stereotypic hand movements. After initial regression, the condition stabilizes and patients usually survive into adulthood. As RTT occurs almost exclusively in females, it has been proposed that RTT is caused by an X-linked dominant mutation with lethality in hemizygous males. Previous exclusion mapping studies using RTT families mapped the locus to Xq28 (refs 6,9,10,11). Using a systematic gene screening approach, we have identified mutations in the gene (MECP2 ) encoding X-linked methyl-CpG-binding protein 2 (MeCP2) as the cause of some cases of RTT. MeCP2 selectively binds CpG dinucleotides in the mammalian genome and mediates transcriptional repression through interaction with histone deacetylase and the corepressor SIN3A (refs 12,13). In 5 of 21 sporadic patients, we found 3 de novo missense mutations in the region encoding the highly conserved methyl-binding domain (MBD) as well as a de novo frameshift and a de novo nonsense mutation, both of which disrupt the transcription repression domain (TRD). In two affected half-sisters of a RTT family, we found segregation of an additional missense mutation not detected in their obligate carrier mother. This suggests that the mother is a germline mosaic for this mutation. Our study reports the first disease-causing mutations in RTT and points to abnormal epigenetic regulation as the mechanism underlying the pathogenesis of RTT.
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PMID:Rett syndrome is caused by mutations in X-linked MECP2, encoding methyl-CpG-binding protein 2. 1050 98

Rett's syndrome is a neurodevelopmental disorder which is caused by a mutation on the x-chromosome; thus, it only affects the female sex. After seemingly normal postnatal development affected girls lose already acquired mental, motoric and social skills. The last stage of the syndrome is characterized by microcephaly, severe mental retardation, spastic paraparesis, epilepsia, respiratory dysrhythmia, neurogenic scoliosis, abnormal joint alignment and muscle contractures. Rett's syndrome is probably the leading cause for progressive mental retardation in girls, but still it is relatively unknown. This paper describes Rett syndrome and its pathophysiology. The following case report discusses special anesthesiological implications due to the immature cardiorespiratory system and describes a coagulation disorder following treatment with valproic acid.
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PMID:[Rett's syndrome: pathophysiology and anesthesiological implications]. 1054 99

We report 5 girls presenting Rett syndrome. All of them were from south Tunisia. They fulfilled the Rett syndrome diagnosis criteria (The Rett syndrome diagnosis criteria work group, 1988). Pregnancy, birth and psychomotor development during the first year of live were normal. The mean age at the onset was 19.8 +/- 2.5 months. The two revealing symptoms were psychomotor regression (3 cases) and epilepsy (2 cases). They were admitted to our ward at a mean age of 4.7 +/- 1.5 years. Clinical presentation was typical of Rett syndrome. Mental retardation, stereotypic hand movement (hand washing/wringing or clapping/tapping) and loss of purposeful manual skills were noted in all cases. Gait was apraxic and increase of head circumference was slowed. Additional features included, respiratory dysfunction (episodic hyperventilation and breath-holding), epilepsy, scoliosis (4 cases), growth retardation and spasticity (3 cases). Electroencephalography showed slow activity with multifocal epileptiform abnormalities. Sleep enhanced these EEG abnormalities. MRI and CT-scan disclosed non specific cortical and sub-cortical atrophy. All cases were isolated and parents were consanguineous in 3 cases. Rett syndrome is relatively frequent in Europe, but in Tunisia this disease remains rare and certainly underdiagnosed.
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PMID:[Rett's syndrome: report of 5 cases in Tunisia]. 1060 40


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