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

Congenital muscular dystrophy (CMD) associated with cerebro-ocular dysplasia named muscle-eye-brain disease (MEB-D) is described in two sisters. Progressive hypotonia, mental retardation and severe visual failure appeared immediately after birth. Pathological examination demonstrated muscular dystrophy, hydrocephalus, type II lissencephaly and defective eye development of foetal origin. The great similarity of the clinical and neuropathological picture of both sisters is in agreement with an autosomal recessive inheritance. Neuropathological distinction between Fukuyama-CMD and MEB-D is a more severe and earlier cerebral developmental defect and the association with ocular dysplasia in MEB-D.
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PMID:Neuropathological findings in muscle-eye-brain disease (MEB-D). Neuropathological delineation of MEB-D from congenital muscular dystrophy of the Fukuyama type. 179 64

Unilateral or bilateral rolandic macrogyria has been described as a cause of epilepsy and, in some cases, retardation. Tissue from the periphery of these lesions shows the changes of focal cortical dysplasia. Evidence reported herein suggests that cortical dysplasia may also be generalized. Two patients with intractable epilepsy and mental retardation had diffusely abnormal, thick cortex, shallow gyri, and poor demarcation of gray and white matter. One patient had an anterior callosotomy that led to considerable improvement of the epilepsy. Cortical layers 5 and 6 could not be differentiated on biopsy material. The white matter was poorly myelinated and contained clusters of heterotopic neurons. This syndrome, a congenital disorder of neuronal migration, with prolonged survival, represents a mild form of lissencephaly. It can be diagnosed during life by computed tomography or magnetic resonance scanning.
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PMID:Generalized cortical dysplasia manifested by diffusely thick cerebral cortex. 249 85

A 4-year-old boy with a history of muscular hypotonia, mental retardation, microcephaly, and generalized convulsions was found at autopsy to have agyria, agenesis of the anterior commissure and posterior corpus callosum as well as an abnormal decussation of pyramidal tracts which descended in the spinal dorsal columns. Postmortem muscular alterations included type IIc fiber hypertrophy and type I fiber grouping, variably expressed in individual muscles and intramuscular fascicles. This may represent a developmental delay compatible with a gestational age between the 34th and 40th week. These studies also indicate the importance of examining multiple samples of postmortem muscles and muscles from patients afflicted with cerebral malformations.
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PMID:Muscular alteration in agyria with pyramidal tract anomaly. 382 54

We report the neuropathologic examination of a neonatal case of Turner's syndrome (45,XO). We have found some mild irregularities in the cortical organization, notably in frontal and hippocampal regions. In the frontal cortex such anomalies affected particularly the more superficial layers essentially sparing the migrating process which was largely achieved in its fundamental phases. The hippocampal dentate gyrus appeared abnormally infolded. The cerebellum was hypoplasic and contained three types of abnormalities, at least: abundant paradentate matrix cell nests, a large mass of dysplastic cerebellar gyri along the ventral wall of the 4th ventricle and, finally, multiple voluminous heterotopias of macroneurons (possibly, Purkinje cells) in the subcortical white matter. In addition, there were two small olivary heterotopias in the medulla oblongata. The correct identification of all neuropathologic anomalies has been possible for having employed the method of whole brain serial sectioning. We have correlated such cortical, cerebellar and truncal abnormalities to those encountered in similar conditions as lissencephaly, Zellweger's disease and chromosomal trisomies. The pathogenetic mechanisms triggered by the absence of an X chromosome can affect the neuronal migration, but only after the cortical hemispheric one has been almost completely ended. This could explain why cerebellar and olivary neuronal migration are exclusively affected, being there the migration process chronologically slowed down during the normal neurogenesis. There means we might date after the 4th fetal months the neuronal migration trouble. Finally, we would suggest the soft cortical changes in such crucial regions as the frontal and hippocampal cortex to be possibly responsible for the degree of mental retardation seen in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Neuropathology of the Turner syndrome]. 408 14

Cerebral cortical dysgenesis (CD) is a heterogeneous disorder of cortical development and organization commonly associated with epilepsy, with a variety of subtypes. We reviewed the clinical, EEG and neuroimaging features in 100 adult patients with CD. There were 39 men and 61 women with a median age of 27 years (range 15-63 years). All patients were referred because of medically refractory epilepsy. Median age at seizure onset was 10 years (range 3 weeks to 39 years); in 30 patients, onset was in adulthood. The epilepsy was classified as generalized in 16 patients and localization-related in 84. Of the latter, the epileptic syndromes in decreasing frequency were frontal (32%), temporal (31%), parietal (14%) and occipital (7%). Only 15% of patients had a history of status epilepticus. Prenatal/perinatal problems were reported in 32 patients but these were severe in only four: exposure to drugs (three) and infection (one) during the first trimester. Delayed developmental milestones were seen in 10%, mental retardation in 9%, additional congenital abnormalities in 4% and neurological deficits in 14% of patients. Diagnosis of CD was based on neuroimaging in 70, pathology in four and both methods in the remaining 26. The following subcategories were identified: agyria/diffuse macrogyria (four patients), focal macrogyria (16), focal polymicrogyria (one), focal macrogyria/polymicrogyria associated with a cleft (11), minor gyral abnormalities (seven), subependymal grey matter heterotopia (20), bilateral subcortical laminar grey matter heterotopia (eight), tuberous sclerosis (five), focal cortical dysplasia/microdysgenesis (seven) and dysembryoplastic neuroepithelial tumours (DNT) (21). Sixty-eight percent of patients had normal CT and 19 out of 36 patients had normal previous conventional MRI. MRI-based hippocampal volume measurements in 47 patients revealed ratios (smaller: larger hippocampus) of < 0.90 in 16, 0.90-0.94 in 14 and > or = 0.95 in 17 patients. EEGs were normal in only five patients. Alpha rhythm was preserved in 78 patients, including one patient with bilateral posterior macrogyria. Localized polymorphic slow activity was present in 43 patients. Five of 68 patients with focal/unilateral CD had only bilateral independent/synchronous spiking and 14 out of 32 with diffuse/bilateral CD only focal/unilateral spiking. In 60 patients with nondiffuse CD or with abnormal gyration or DNT, the epileptiform abnormalities were less extensive than coextensive with the lesion in 28, more extensive than and overlapped the lesion in 18 and remote from the lesion in five; nine patients did not have epileptiform abnormalities. There was poor correlation between the epileptic syndromes and EEG abnormalities and the location/extent of CD as defined by MRI and pathology.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Abnormalities of gyration, heterotopias, tuberous sclerosis, focal cortical dysplasia, microdysgenesis, dysembryoplastic neuroepithelial tumour and dysgenesis of the archicortex in epilepsy. Clinical, EEG and neuroimaging features in 100 adult patients. 760 83

Subcortical laminar heterotopia (band heterotopia) is a brain malformation now recognized by MRI. We report 3 families (2 previously described) in which several members had subcortical laminar heterotopia or a more severe malformation (agyria/pachygyria). In these families, subcortical laminar heterotopia were observed in women and were associated with epilepsy or slight mental retardation depending on the extend of heterotopia. Males had lissencephaly with refractory epilepsy and severe mental retardation. The pedigrees of these families demonstrate that these 2 malformations originate from a single genetic origin. A single X-linked dominant gene is postulated. Diagnosis of subcortical laminar heterotopia in a female or lissencephaly in a male (except in the case of Miller-Dieker syndrome) requires appropriate genetic counselling in the family: brain imaging should be performed in relatives.
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PMID:[Subcortical laminal heterotopia and lissencephaly: cerebral malformations of X-linked inheritance]. 767 53

A half cryptic translocation t(9;17) (p24.2; p13.3) was detected in a large family by fluorescence in situ hybridisation. Unbalanced karyotypes resulted either in lissencephaly and early death or in mental retardation, microcephaly, high arched palate, and deformities of the vertebrae. Some of the features observed in affected persons are characteristic of known syndromes involving either 17p or 9p.
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PMID:Familial half cryptic translocation t(9;17). 781 41

We describe two brothers with mental retardation and refractory epilepsy. MRI revealed symmetrical agyria-pachygyria of the temporo-occipito-parietal regions, areas of deeply infolded polymicrogyric parietal cortex, and dilated occipital horns (colpocephaly). The stereotyped clinical, EEG, and MRI findings suggest that this may be a distinct inherited condition and imply that agyria-pachygyria with polymicrogyria is not always sporadic.
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PMID:Posterior agyria-pachygyria with polymicrogyria: evidence for an inherited neuronal migration disorder. 750 Nov 86

Over the past few years, molecular neurogenetics has developed into one of the most promising and active research fields. The new discipline applies modern molecular genetic techniques to the investigation of classical neurological disorders. In the following article, a definition of neurogenetic disease is introduced, the molecular basis of four groups of neurogenetic disorders is described and recent diagnostic developments are presented. The first group of diseases is caused by trinucleotide expansions. "Expanding" trinucleotide repeats were not known to occur in any species until about three years ago. Today, disorders such as Huntington's disease, spinocerebellar ataxia type 1, fragile X mental retardation, spinobulbar muscular atrophy and myotonic dystrophy are all known to be caused by the expansion of trinucleotides. The second group is characterized by chromosomal deletions or uniparental disomies. Lissencephaly and the Miller-Dieker syndrome, Prader-Willi and Angelman syndromes and Duchenne and Becker muscular dystrophies belong to this category. The third group includes those neurogenetic disorders that are mainly caused by point mutations such as the X-linked leukodystrophies, including Pelizaeus-Merzbacher disease and adrenoleukodystrophy, Charcot-Marie-Tooth syndrome type 1, familial forms of amyotrophic lateral sclerosis, several types of craniosynostoses and some CNS tumor syndromes. Finally, Alzheimer's and Parkinson's disease are discussed as representatives of group four, i.e. genetically heterogeneous neurological disorders.
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PMID:Molecular basis and diagnosis of neurogenetic disorders. 796 63

With the development of modern imaging techniques, disturbances of neuronal migration appear to be a major cause of epilepsy, mental retardation and chronic neurological disability in childhood. Sixty-nine cases are presented, including 46 of diffuse migration abnormalities and 23 of localized dysplasia. Patients with diffuse migration disorders presented with mental retardation, gross motor impairment and severe seizure disorders whereas in those with focal anomalies, epilepsy was the chief complaint. Magnetic resonance imaging, although usually diagnostic of migration disorders often does not allow definition of the pathologic type. Some EEG patterns, such as high amplitude fast rhythms or the theta-delta pattern are highly suggestive. Most cases of abnormal migration are sporadic and probably acquired. Some are due to chromosomal anomalies, especially of chromosome 17p where a gene for lissencephaly has been mapped. Familial cases occur with both recessive and possibly dominant inheritance. Epilepsy due to migration abnormalities is often intractable. Resection of dysplastic cortex may be effective for localized disease and callosotomy has been proposed for diffuse anomalies.
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PMID:The place of neuronal migration abnormalities in child neurology. 800 Sep 73


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