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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lissencephaly has been long maintained a malformation involving only the brain. Classic lissencephaly includes agyria and pachygyria and it is the most severe form of malformations derived from abnormal neuronal migration. It is defined as a smooth or nearly smooth cerebral surface with absence of normal sulci and gyria. It encompasses a group of syndromes which show many different clinical conditions. Four groups are actually distinguished: classic lissencephaly variants, other lissencephalies including forms with unknown pathogenesis, microlissencephaly spectrum and Cobblestone cortical malformations. Several genes and proteins are involved in this syndromic spectrum and each year new molecular data are reported in the literature: classifications in this sense are always in progress. Lissencephaly now is recognised to involve not only the brain but also several other organs and districts including eyes, face, muscles, genital organs, heart and bones. Mental retardation and different form of epilepsies usually drug-resistant are the main clinical signs. The Authors in this topic discuss on this subject, underlying the different forms of lissencephaly their wide heterogeneity and the complex involvement of several organs.
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PMID:Lissencephalic syndromes: brain and beyond. 2003 30

Congenital ataxia with cerebellar hypoplasia is a heterogeneous group of disorders that presents with motor disability, hypotonia, incoordination, and impaired motor development. Among these, disequilibrium syndrome describes a constellation of findings including non-progressive cerebellar ataxia, mental retardation, and cerebellar hypoplasia following an autosomal recessive pattern of inheritance and can be caused by mutations in the Very Low Density Lipoprotein Receptor (VLDLR). Interestingly, while the majority of patients with VLDL-associated cerebellar hypoplasia in the literature use bipedal gait, the previously reported patients of Turkish decent have demonstrated similar neurological sequelae, but rely on quadrupedal gait. We present a consanguinous Turkish family with two siblings with cerebellar atrophy, predominantly frontal pachygyria and ataxic bipedal gait, who were found to have a novel homozygous deletion in the VLDLR gene identified by using high-density single nucleotide polymorphism microarrays for homozygosity mapping and identification of CNVs within these regions. Discovery of disease causing homozygous deletions in the present Turkish family capable of maintaining bipedal movement exemplifies the phenotypic heterogeneity of VLDLR-associated cerebellar hypoplasia and ataxia.
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PMID:Novel VLDLR microdeletion identified in two Turkish siblings with pachygyria and pontocerebellar atrophy. 2008 5

We describe a 16-year-old girl with mental retardation, myoclonic epilepsy, ataxia, mitochondrial myopathy, sensorineural hearing loss, lactic acidosis, and MRI evidence of diffuse subcortical laminar heterotopia and agyria/pachygyria. Restriction fragment length polymorphism (RFLP) and DNA sequence analyses revealed two pathogenic mutations: a heteroplasmic m.3243A>G in muscle and blood, and a new heterozygous insertion at nt697 in the doublecortin gene (DCX), resulting in a frameshift after amino acid residue 232, with a premature stop codon at amino acid residue 244. This is yet another example of genetic "double trouble" resulting in a complex phenotype.
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PMID:Coexistence of mitochondrial and nuclear DNA mutations in a woman with mitochondrial encephalomyopathy and double cortex. 2043 51

Primary microcephaly is an autosomal recessive disorder characterized by smaller than normal brain size and mental retardation. It is genetically heterogeneous with seven loci: MCPH1-MCPH7. We have previously reported genetic analysis of 35 families, including the identification of the MCPH7 gene STIL. Of the 35 families, three families showed linkage to the MCPH2 locus. Recent whole-exome sequencing studies have shown that the WDR62 gene, located in the MCPH2 candidate region, is mutated in patients with severe brain malformations. We therefore sequenced the WDR62 gene in our MCPH2 families and identified two novel homozygous protein truncating mutations in two families. Affected individuals in the two families had pachygyria, microlissencephaly, band heterotopias, gyral thickening, and dysplastic cortex. Using immunofluorescence study, we showed that, as with other MCPH proteins, WDR62 localizes to centrosomes in A549, HepG2, and HaCaT cells. In addition, WDR62 was also localized to nucleoli. Bioinformatics analysis predicted two overlapping nuclear localization signals and multiple WD-40 repeats in WDR62. Two other groups have also recently identified WDR62 mutations in MCPH2 families. Our results therefore add further evidence that WDR62 is the MCPH2 gene. The present findings will be helpful in genetic diagnosis of patients linked to the MCPH2 locus.
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PMID:Mutations in WDR62, encoding a centrosomal and nuclear protein, in Indian primary microcephaly families with cortical malformations. 2149 9

Congenital cytomegalovirus (CMV) infection is the most common vertically transmitted disease with the rate of the infection ranging from 0.2 to 2.4% in newborn infants. Congenital CMV infection causes multiorgan affection, but the most severe and permanent sequelae are those affecting central nervous system such as mental retardation, cerebral palsy, sensorineural hearing loss, chorioretinitis and seizures as a result of direct interference of the virus with neurogenesis. The time of acquiring infection is strongly connected to the level of child's disability. Infection in early pregnancy results in severe neurological sequelae, while later infection has less prominent signs. Radiological findings show connection between onset of infection and brain imaging, from lissencephaly, pachygyria, polymicrogyria, schizencephaly, calcification, cerebellar hypoplasia and/or hypoplasia/agenesis of corpus callosum as a result of an early infection, to white matter abnormalities including disturbed myelination as a result of a late infection. We present nine patients with proven congenital CMV infection and malformations of cortical development and their computed tomography/magnetic resonance (CT/MRI) findings along with clinical assessments. According to CT/MRI results we assume that two of our children with lissencephaly had an early onset of infection. The other seven with less severe cortical dysplasia in form of pachy/polymicrogyria were probably infected later Cerebellar hypoplasia and/or calcifications in our patients also confirm an early onset of infection. Developmental outcome in all of our children was poor: moderate to severe psychomotor retardation has been diagnosed in all children; five of them have developed cerebral palsy (four have bilateral spastic and one dyskinetic) and one is estimated to have minor motor dysfunction. Seven out of nine developed epilepsy, chorioretinitis was found in three of them and sensorineural deafness in two of them. All of our children, except one, were presented by symptomatic infection, yet only four of them were recognized at birth. Therefore, congenital CMV infection should be considered as one of the reasons for childhood disability more often.
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PMID:Malformations of cortical development in children with congenital cytomegalovirus infection - A study of nine children with proven congenital cytomegalovirus infection. 2164 39

Dyke-Davidoff-Masson syndrome is a relatively rare syndrome with its typical clinical and radiological features including facial asymmetry, hemiplegia, cerebral hemiatrophy, mental retardation with calvarial thickening, hypertrophy of sinuses and elevated petrous ridge on imaging. We present here a case of congenital type Dyke-Davidoff-Masson syndrome with some additional features in the form of microcephaly, hypospadias and pachygyria.
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PMID:Dyke-Davidoff-Masson syndrome: a clinicoradiological amalgam. 2489 88

22q11.2 microduplication syndrome was recently described as a new disorder with variable clinical features that ranged from normal to mental retardation and with congenital defects. According to published reports, majority of patients with 22q11.2 duplications inherit these from unaffected parents rather than by de novo mutations, which is different from most microduplication/microdeletion syndromes. In this study, we report a patient that carried a paternally inherited atypical 1.33Mb duplication at 22q11.23. The proband (or proposita) presented with hypotonia, feeding difficulties, intractable epilepsy, hearing disability, and pachygyria. A pachygyria phenotype had not been previously reported to be associated with a 22q11 microduplication syndrome. Cytogenetic and molecular genetic analyses based on standard G-banding, SNP array, and fluorescence in situ hybridization were performed for the proband and her parents. An atypical 1.33Mb duplication at 22q11.23 was detected in both the proband and her father. Thus, our findings verify the pathogenicity and diverse phenotypes of 22q11.2 microduplication and expand its phenotypic spectrum.
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PMID:Pachygyria, seizures, hypotonia, and growth retardation in a patient with an atypical 1.33Mb inherited microduplication at 22q11.23. 2609 17

Pachygyria is considered a subtype of lissencephaly which, in turn, is a spectrum of disorders caused by abnormal neuronal migration. Clinical presentation in this disorder may be varied including microcephaly, developmental delay, facial dysmorphism, seizures, and mental retardation. Magnetic resonance imaging (MRI) of brain identifies the exact nature and extent of the disease and helps in delineating further plan of management. A Tigroid pattern on axial MRI scan and leopard pattern on a sagittal plane has been classically reported in disorders of myelin formation such as metachromatic leukodystrophy and Pelizaeus-Merzbacher disease. We present here a case of pachygyria who presented to us with some atypical features including "tigroid-like stripes" and "leopard-like pattern" on MRI brain which has not been reported in the medical literature previously.
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PMID:"Reverse Tigroid" Pattern in Pachygyria: A Novel Finding. 2719 81

Lissencephaly is a rare disorder due to abnormal neural migration, causing neurological impairment and clinically characterised by mental retardation and epilepsy. Any disturbance of the visual pathway can cause loss of vision. The authors describe a case of a 6-year-old boy referred to the ophthalmologist presenting poor bilateral vision. This child had no other known medical conditions, and neurological examination was completely normal. Only when a magnetic resonance imaging was made that a lissencephaly-pachygyria with band heterotopia mostly occipital was noted. Cortical defects should be considered in order to diagnosis some visual defects in children.
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PMID:Visual Impairment Due to Lissencephaly. 2792 11


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