Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sialidase (neuraminidase, EC 3.2.1.18) catalyses the hydrolysis of terminal sialic acid residues of glyconjugates. Sialidase has been well studied in viruses and bacteria where it destroys the sialic acid-containing receptors at the surface of host cells, and mobilizes bacterial nutrients. In mammals, three types of sialidases, lysosomal, plasma membrane and cytosolic, have been described. For lysosomal sialidase in humans, the primary genetic deficiency results in an autosomal recessive disease, sialidosis, associated with tissue accumulation and urinary excretion of sialylated oligosaccharides and glycolipids. Sialidosis includes two main clinical variants: late-onset, sialidosis type I, characterized by bilateral macular cherry-red spots and myoclonus, and infantile-onset, sialidosis type II, characterized by skeletal dysplasia, mental retardation and hepatosplenomegaly. We report the identification of human lysosomal sialidase cDNA, its cloning, sequencing and expression. Examination of six sialidosis patients revealed three mutations, one frameshift insertion and two missense. We mapped the lysosomal sialidase gene to human chromosome 6 (6p21.3), which is consistent with the previous chromosomal assignment of this gene in proximity to the HLA locus.
 ...
PMID:Cloning, expression and chromosomal mapping of human lysosomal sialidase and characterization of mutations in sialidosis. 905 50

Cortical malformations such as cortical dysplasia and heterotopia constitute the underlying pathology of epilepsy and mental retardation. It is thus important to elucidate the pathogenesis of these migration disorders from the neuropathological viewpoint based upon animal experiments. In this review, I describe the experiment in which low-dose prenatal X-or gamma-irradiation was performed at the mid-gestational period of mice or rats. Low-dose irradiation as low as 150 mGy induced decelerated migration of cortical neurons during the embryonic period together with a changed pattern of cell adhesion molecule, N-CAM. In addition, the effect of radiation remained at least up until 3-week postnatal as disorganized neuronal allocation with respect to the birthdate. With time of further maturation in the neocortex, however, the architecture, in terms of the pattern of distribution of the labeled neurons, returned closely to that found in non-irradiated control animals. Considering the fact that the number of labeled cells per unit cortical area decreased considerably from 3-week to 8-week postnatal, it is conceivable that apoptotic cell death might have occurred in aberrantly placed neurons. Recent progress of molecular genetical approach to human hereditary neurodevelopmental diseases is briefly reviewed, since it greatly contributes to our understanding on the pathogenesis of neuronal migration disorders.
 ...
PMID:[Pathogenesis of the neuronal migration disorder, with special reference to the animal model of prenatal exposure to low-dose ionizing radiation]. 907 Nov 86

Osteopathia striata with cranial sclerosis (OS-CS) is a bone dysplasia characterized by hypertelorism, macrocephaly, frontal bossing, broad nasal bridge, palate anomalies, hearing deficits, and mental retardation. The radiographic findings include cranial sclerosis, linear striations in the long bones and iliac wings, small poorly aerated sinuses, scoliosis, and increased bone density. The sensory deficits are disabling, but the condition generally is not life threatening. We describe 4 brothers with the characteristics of OS-CS, 3 of whom have died from more serious complications of the disorder. The mother of these children, and her only daughter, have the mildest phenotype with the typical linear striations in the long bones and macrocephaly. OS-CS is thought to be autosomal dominant with complete penetrance and variable expressivity. Our observations could be consistent with X-linkage, since there is milder expression in the female relatives. In addition, we recognize absent fibulae, malrotation, and omphalocele as new manifestations as well as congenital heart disease.
 ...
PMID:Further clinical delineation and increased morbidity in males with osteopathia striata with cranial sclerosis: an X-linked disorder? 912 36

We report a case of linear nevus sebaceous syndrome with seizure, mental retardation, and hemiparesis. Magnetic resonance imaging (MRI) clearly demonstrated associated brain malformations of unilateral megalencephaly with cortical dysplasia and white matter change ipsilateral to the sebaceous nevi of the face and neck. Although magnetic resonance angiography (MRA) demonstrated only distortion of the main cerebral arteries without any occlusive or dysplastic findings, single photon emission computed tomography (SPECT) using [123I]N-Isopropyl-p-iodoamphetamine (IMP) revealed hypoperfusion in the affected cerebral hemisphere.
 ...
PMID:Unilateral megalencephaly in linear nevus sebaceous syndrome: a neuroradiological case report. 913 88

Six cases of the CHARGE association are described that were encountered consecutively at an institute for the deaf. Five of them showed external ear anomalies and according to expectations all of them showed some degree of hearing impairment: two had moderate mixed hearing loss; three had severe to profound sensorineural hearing loss; and one was completely deaf. In addition, they all had vestibular areflexia and the five cases examined with computer tomography of the petrosal bones showed aplasia of the semicircular canals. One case with poor visual acuity also showed subnormal optokinetic responses and horizontal pendular nystagmus during visual fixation. All these children were initially diagnosed as having severe psychomotor retardation, because of their failure to acquire speech and their delayed motor skill development. Given the fact that (mild) mental retardation was found in only one case, the delayed development could at least in part have been caused by vestibular areflexia. The vestibular findings support previously reported temporal bone findings that indicate dysplasia or aplasia of the superior part of the labyrinth. Early detection of the full extent of (multiple) sensory deficits is necessary in children with the CHARGE association who have similar abnormalities, because aggressive intervention and special educational support are likely to be of great benefit to sensorimotor development.
 ...
PMID:Vestibular areflexia as a cause of delayed motor skill development in children with the CHARGE association. 915 48

Wolcott-Rallison syndrome is a rare autosomal recessive condition characterized by diabetes mellitus arising in early infancy and multiple epiphyseal dysplasia. To date, nine cases have been described in the world literature. We report an affected girl who died at the age of 4 years and on whom a full autopsy was performed. In addition to neonatal diabetes mellitus and epiphyseal dysplasia, this child had mental retardation and recurrent episodes of self-limiting hepatic failure. Autopsy revealed severe pancreatic hypoplasia and markedly abnormal pancreatic histology, while histology of the bone was consistent with epiphyseal dysplasia. There was laryngeal stenosis and pulmonary hypoplasia. The heart was enlarged with mitral value dysplasia and stenosis, left atrial dilatation, left ventricular hypertrophy, and endocardial fibroelastosis. Examination of the central nervous system showed arrhinencephaly and cerebellar cortical dysplasia. The liver showed minor histological abnormalities but no features were present to account for the recurrent hepatic failure. In addition to Wolcott-Rallison syndrome this child had a deletion at 15q11-12 in 65% of her cells.
 ...
PMID:Autopsy findings in the Wolcott-Rallison syndrome. 918 26

The heterogeneous group of craniotubular dysplasias is characterized by modeling errors of the craniofacial and tubular bones. Some conditions in this category cause not only skeletal abnormalities but also a variety of mesoectodermal dysplasias, as exemplified in Lenz-Majewski syndrome (MIM 151050), which comprises craniodiaphyseal dysplasia, failure to thrive, mental retardation, proximal symphalangism, enamel hypoplasia, and loose skin. We report on a boy with a hitherto unknown multisystem disorder, including skeletal changes that were regarded as a form of craniotubular dysplasia. The patient had a large head, exophthalmos, a broad nasal root, anteverted nostrils, large auricles, thick lips, micrognathia, severe postnatal growth retardation with emaciation, severe mental retardation, sparse hair growth, enamel hypoplasia, and thin, loose skin with hyperlaxity. Skeletal changes consisted of thickened calvaria, sclerosis of the skull base and facial bones, thick ribs, and metaphyseal undermodeling of the tubular bones. In addition, generalized osteopenia was evident. The present disorder overlaps phenotypically with Lenz-Majewski syndrome; nevertheless, the absence of diaphyseal hyperostosis and proximal symphalangism in the present patient was not consistent with Lenz-Majewski syndrome.
 ...
PMID:Craniotubular dysplasia with severe postnatal growth retardation, mental retardation, ectodermal dysplasia, and loose skin: Lenz-Majewski-like syndrome. 921 75

Among the variable manifesting conditions of neuronal migration disorders, mental retardation, motor disturbance and epilepsy are the main features of developmental disabilities. We analyzed the relationship between clinical symptoms and magnetic resonance (MR) images, including surface anatomy scan (SAS). Thirty nine patients (23 males, 16 females; mean age 6.1 years) with neuronal migration disorders were studied. The diagnoses were cerebral palsy in 23 cases, mental retardation in 4. West syndrome in 4, Fukuyama type congenital muscular dystrophy (FCMD) in 6. Walker-Warburg syndrome in 1 and Dubowitz syndrome in 1. Cortical dysplasias were classified into the following 7 groups, mainly based on the SAS findings: complete agyria (AG 1), mixture of agyria and pachygyria (AG 2), bilateral complete pachygyria (BP 1), diffuse pachygyria with marked widening of the bilateral superior frontal gyrus (BP 2), unilateral pachygyria with hemispheric atrophy or hemimegalencephaly UP), focal cortical dysplasia (FP) and other findings such as solitary schizencephaly (Others). Most cases of AG 1 and AG 2 showed spastic quadriplegia (6/7) and symptomatic generalized epilepsy (5/7), whereas cases of BP1 showed spasticity only in 1/8 and epilepsy in 7/8. Hemiplegia was observed in 6/7 of UP, 2/8 of FP and 2/4 of Others. Partial epilepsy was observed in 2/7 of UP and 1/8 of FP. Intellectual level was variable in BP 1, UP, FP and Others, but all cases showed severe mental retardation in AG 1, AG 2 and BP 2. BP 2 was observed in all cases of typical FCMD (5/5). The birth weight was less than 2,500 g in 6/7 of UP. The structural findings well correlated with clinical symptoms and epileptic seizure types. The surface anatomy scan was a very useful technique for detecting cortical dysplasias.
 ...
PMID:[The relationship between MR images and clinical findings in neuronal migration disorders]. 924 87

Dyggve-Melchior-Clausen syndrome without mental retardation (Smith-McCort dysplasia) (SM) has clinical and radiographic findings similar to those of Dyggve-Melchior-Clausen syndrome (DMC) except for mental retardation. Iliac crest biopsies from two patients with SM were examined. The lace-like appearance of the iliac crests, which is a characteristic radiological sign of SM and DMC, was caused by bone tissue deposited in a wavy pattern at the osteochondral junction. The growth plate showed abnormal enchondral ossification with no columnarization of chondrocytes. Electron microscopy demonstrated chondrocytes with dilated cisternae of rough endoplasmic reticulum containing fine granular or amorphous material, similar to those reported in cases of DMC. Thus, SM has pathologic changes in common with DMC as a rough endoplasmic reticulum storage disorder, even though the mental condition is different.
 ...
PMID:Dyggve-Melchior-Clausen syndrome without mental retardation (Smith-McCort dysplasia): morphological findings in the growth plate of the iliac crest. 929 67

Bilateral periventricular nodular heterotopia (BPNH) is a recently recognized malformation of neuronal migration, and perhaps proliferation, in which nodular masses of gray matter line the walls of the lateral ventricles. Most affected individuals have epilepsy and normal intelligence with no other congenital anomalies. A striking skew of the sex ratio has been observed because 31 of 38 probands have been female, and one gene associated with BPNH was recently mapped to chromosome Xq28. We report three unrelated boys with a new multiple congenital anomaly-mental retardation syndrome that consists of BPNH, cerebellar hypoplasia, severe mental retardation, epilepsy, and syndactyly. Variable abnormalities included focal or regional cortical dysplasia, cataracts, and hypospadius. We hypothesize that this syndrome involves the same Xq28 locus as isolated BPNH, and we review the expanding number of syndromes associated with BPNH.
 ...
PMID:Bilateral periventricular nodular heterotopia with mental retardation and syndactyly in boys: a new X-linked mental retardation syndrome. 933 87


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>