Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0917816 (mental retardation)
 15,867 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Darier's disease, also known as keratosis follicularis, is an uncommon autosomal dominant disorder that may also occur as a sporadic mutation. It is characterized by multiple eruptions of hyperkeratotic or crusted papules at seborrheic areas with histologic acantholysis and dyskeratosis. It usually begins in the first or second decade of life and is equally prevalent in men and women. Darier's disease is caused by mutations in the ATP2A2 gene, which maps to chromosome 12q23-q24.1 and encodes the sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA2). The co-occurrence of various neurologic and psychiatric diseases with Darier's disease has been reported, including mood disorders, epilepsy, mental retardation, slowly progressive encephalopathy, and schizophrenia. Linkage studies using the association between these disorders and Darier's disease to determine the gene locus of these psychiatric disorders inferred the presence of a bipolar susceptibility gene on chromosome 12q23-q24.1 in the region of the Darier's disease gene (DAR). We report a case of Darier's disease of more than 40 years' duration and bipolar I disorder of 30 years' duration in a 52-year-old man, and provide a brief review of the literature.
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PMID:Darier's disease associated with bipolar affective disorder: a case report. 1267 38

We reported three term or near-term infants with parasagittal infarcts. Their Apgar scores were low and the amniotic fluid was meconium-stained. Resuscitation was necessary immediately after birth, but they were not stuporous and no neurological abnormalities were recognized on admission. They showed metabolic acidosis and transient hypoglycemia, and two showed hematoemesis. Seizures were observed between 2 and 15 h of age in all of them. Electroencephalography demonstrated moderate or severe depression, and CT demonstrated bilateral abnormal low densities in the border zones of the middle and posterior cerebral arteries. Two of them had mental retardation and epilepsy, although the other exhibited normal development. Our infants suggest that neonatal seizures can also occur in infants with hypoxic ischemic encephalopathy without apparent neurological abnormalities.
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PMID:Hypoxic ischemic encephalopathy associated with neonatal seizures without other neurological abnormalities. 1268 4

Rett syndrome (RTT) is a severe neurodevelopmental disorder affecting almost exclusively girls. It is currently considered a monogenic X-linked dominant disorder due to mutations in MECP2 gene, encoding the methyl-CpG binding protein 2. A few RTT male cases, resulting from mosaicism for MECP2 mutations, have been reported. Male germline MECP2 mutations cause either severe encephalopathy with death at birth (usually in brothers of classical RTT females) or X-linked recessive mental retardation (XLMR). To date the wide phenotypic heterogeneity associated with MECP2 mutations in females (from classical RTT to healthy carriers) has been explained by differences in X chromosome inactivation. However, conflicting results have been obtained in different studies, with both random and highly skewed X-inactivation reported in healthy carrier females. Consequently it is possible that mechanisms other than X-inactivation play a role in the expressivity of MECP2 mutations. To explain the phenotypic heterogeneity associated with MECP2 mutations we propose a digenic model in which the presence of a "mutated" allele in a second gene, leading to a less functional protein, determines the clinical severity of the MECP2 mutation. The model is supported by the identification of the same mutation in XLMR and RTT cases. The carrier mothers of XLMR families are clinically asymptomatic and present balanced X chromosome inactivation. Therefore the same mutation arising in different genetic backgrounds can cause XLMR in males, remain silent in the carrier females and cause classic RTT in females. MECP2 mutations account for approximately 70-80% of classic RTT cases. MECP2 negative cases might result from mutations in noncoding regions of MECP2 gene. Alternatively, these cases might be due to mutations in other genes (locus heterogeneity). This hypothesis is supported by the identification of several chromosomal rearrangements in MECP2 negative patients with RTT and RTT-like phenotypes. MeCP2 is considered a general transcriptional repressor. However, conditional mouse mutants with selective loss of Mecp2 in the brain develop clinical manifestations similar to RTT, indicating that MECP2 is exclusively required for central nervous system function. The involvement of MeCP2 in methylation-specific transcriptional repression suggests that MECP2 related disorders result from dysregulated gene expression. Studies on gene expression have been performed in mouse and human brains. A relatively small number of gene expression changes were identified. It is possible that MeCP2 causes dysregulation of a very small subset of genes that are not detected with this method of analysis, or that very subtle changes in many genes cause the neuronal phenotype.
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PMID:Rett syndrome: the complex nature of a monogenic disease. 1275 Aug 21

Plasticity includes the brain's capacity to be shaped or moulded by experience, the capacity to learn and remember, and the ability to reorganize and recover after injury. Mechanisms for plasticity include activity-dependent refinement of neuronal connections and synaptic plasticity as a substrate for learning and memory. The molecular mechanisms for these processes utilize signalling cascades that relay messages from synaptic receptors to the nucleus and the cytoskeleton to control the structure of axons and dendrites. Several paediatric neurological disorders such as neurofibromatosis-1, Fragile X syndrome, Rett syndrome, and other syndromic and non-specific forms of mental retardation involve lesions in these signalling pathways. Acquired disorders such as hypoxic-ischaemic encephalopathy, lead poisoning and epilepsy also involve signalling pathways including excitatory glutamate receptors. Information about these 'plasticity pathways' is useful for understanding their pathophysiology and potential therapy.
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PMID:Brain plasticity in paediatric neurology. 1278 36

Hypoxic-ischemic encephalopathy due to fetal or neonatal asphyxia is a major cause of acute mortality and chronic disability involving cerebral palsy, seizures, and mental retardation. The gestational age of the infant is one of the main variables determining the neuropathological picture of hypoxic-ischemic brain injury, and ulegyria (one of its neuropathological correlates) typically affects full-term infants. The damage usually involves the deeper sulcal portion of the convolutions while sparing the crowns, and includes subcortical white matter atrophy and gliosis. The aim of this study was to characterize the electroclinical features of hypoxic-ischemic encephalopathy when ulegyria is one of its main neuropathological features. To this end, nine patients with MRI-proven ulegyria and epilepsy underwent a complete neurological work-up. The ulegyric lesions were mainly distributed in the parasagittal watershed areas and frequently associated with other hypoxic-ischemic lesions. The neurological picture was characterized in most patients by mental retardation, motor deficits, and drug-refractory partial epilepsy. The ulegyria in our patients was associated with a complex clinical picture: epilepsy was a prominent component, and its severity directly correlated with the extent of the ulegyria and the associated hypoxic-ischemic lesions. Drug refractoriness was an almost constant correlate of this form of symptomatic epilepsy.
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PMID:Epileptic and imaging findings in perinatal hypoxic-ischemic encephalopathy with ulegyria. 1297 77

Rett syndrome (RTT) is one of the most common neurodevelopmental disorders in females. The disease is caused by mutations in the methyl-CpG-binding protein 2 gene (MECP2), and various mutations have been reported. The phenotypic spectrum in both female and male patients is diverse, ranging from very mild to congenital encephalopathy and prenatal lethality. In this study, the question was addressed as to whether implementation of systematic screening of MECP2 in patients with an unexplained mental retardation in DNA diagnostics would be reasonable, and the spectrum of phenotypes resulting from mutations in this gene was further explored. Mutational analysis of MECP2 was performed in mentally retarded female patients who were negative for FMR1 CGG repeat expansion, in male and female patients with clinical features suggestive of either Angelman or Prader-Willi syndrome without methylation defects on chromosome 15q11-q13. In the cohort of females negative for the molecular Fragile-X studies (N=92), one nonsense mutation (p.Q406X) was found. In the cohort of Angelman-negative patients (N=63), two missense mutations (p.R133C in a female patient and a mosaic p.T158M in a male patient) were found, which have been reported many times in patients with classical RTT syndrome. In the Prader-Willi-negative group (N=98), no pathogenic mutations were found. The results support testing of patients with features suggestive of Angelman syndrome, but without methylation defects on chromosome 15q11-q13 for mutations in MECP2. In the remaining patients with unexplained mental retardation, additional clinical features should determine whether analysis of MECP2 is indicated.
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PMID:MECP2 analysis in mentally retarded patients: implications for routine DNA diagnostics. 1456 Mar 7

Few studies have focused on the clinical, neurophysiological and prognostic features of adult epileptic patients with malformation of cortical development. We reviewed the clinical data of a series of sixty adult epileptic patients with different types of malformation of cortical development, who had been followed at the Epilepsy Centre of the Department of Neurological Sciences of the University of Bologna, with particular attention to age at seizure onset, mental retardation, response to therapy, and EEG features. The heterogeneity of our population, especially when divided into the different groups of malformation of cortical development, precluded any general conclusions, but we stress the following aspects: 1). epilepsy due to malformation of cortical development may begin in adolescents and young adults; 2). epileptic seizures with clinical and polygraphic features of infantile spasms may persist into adulthood; 3). complex cortical malformation is not necessarily associated with severe epileptic encephalopathy. In periventricular nodular heterotopias, the largest in our series (nine patients), age at onset of seizures, response to therapy and mental deterioration differed according to the presence of nodules confined to the ventricular wall ('pure' form) or periventricular nodules associated with other cerebral cortical malformations ('plus' form).
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PMID:Malformation of cortical development in adult patients. 1461 26

Clinical disorders of brain plasticity are common in the practice of child neurology. Children have an enhanced capacity for brain plasticity compared to adults as demonstrated by their superior ability to learn a second language or their capacity to recover from brain injuries or radical surgery such as hemispherectomy for epilepsy. Basic mechanisms that support plasticity during development include persistence of neurogenesis in some parts of the brain, elimination of neurons through apoptosis or programmed cell death, postnatal proliferation and pruning of synapses, and activity-dependent refinement of neuronal connections. Brain plasticity in children can be divided into four types: adaptive plasticity that enhances skill development or recovery from brain injury; impaired plasticity associated with cognitive impairment; excessive plasticity leading to maladaptive brain circuits; and plasticity that becomes the brain's 'Achilles' Heel' because makes it vulnerable to injury. A broad group of pediatric neurologic disorders can be understood in terms of their impact on fundamental mechanisms for brain plasticity. These include neurofibromatosis, tuberous sclerosis, Fragile X syndrome, other inherited forms of mental retardation, cretinism, Coffin-Lowry syndrome, lead poisoning, Rett syndrome, epilepsy, hypoxic-ischemic encephalopathy and cerebral palsy.
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PMID:Clinical disorders of brain plasticity. 1503 25

Lennox-Gastaut syndrome is an epileptic encephalopathy characterized by multiple seizure types, mental retardation, and a slow spike-and-wave pattern on electroencephalography. Medical intractability is common. We identified a case series of six patients diagnosed with Lennox-Gastaut syndrome in which levetiracetam was initiated as add-on therapy for the management of seizures. At follow-up, four patients experienced 100% reduction of their myoclonic seizures; two patients had greater than 50% reduction of their atonic seizures, and four patients experienced 100% reduction in their generalized tonic-clonic seizures. Tonic seizures were not responsive to treatment. The most common side effect was irritability; the most positive change involved alertness. In this small sample, levetiracetam appeared effective in reducing seizures in Lennox-Gastaut syndrome. This preliminary study is limited by its retrospective design and small number of patients, but positive findings warrant a larger scale, multicenter study.
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PMID:Levetiracetam in the treatment of Lennox-Gastaut syndrome. 1508 3

Mutations in the gene coding for methyl-CpG-binding protein 2 (MECP2) cause Rett syndrome (RTT) and have also been reported in a number of X-linked mental retardation syndromes. Furthermore, putative mutations recently have been described in a few autistic patients and a boy with language disorder and schizophrenia. In this study, DNA samples from individuals with schizophrenia and other psychiatric diseases were scanned in order to explore whether the phenotypic spectrum of mutations in the MECP2 gene can extend beyond the traditional diagnoses of RTT in females and severe neonatal encephalopathy in males. The coding regions, adjacent splicing junctions, and highly conserved segments of the 3'-untranslated region (3'-UTR) were examined in 214 patients, including 106 with schizophrenia, 24 with autism, and 84 patients with other psychiatric diseases by detection of virtually all mutations-single strand conformation polymorphism (SSCP) (DOVAM-S). To our knowledge, this is the first analysis of variants in conserved regions of the 3'-UTR of this gene. A total of 5.2 kb per haploid gene was analyzed (1.5 Mb for 214 patients). A higher frequency of missense and 3'-UTR variants was found in autism. One missense and two 3'-UTR variants were found in 24 patients with autism versus one patient with a missense change in 144 ethnically similar individuals without autism (P = 0.009). These mutations suggest that a possible association between MECP2 mutations and autism may warrant further study.
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PMID:MECP2 structural and 3'-UTR variants in schizophrenia, autism and other psychiatric diseases: a possible association with autism. 1521 31


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