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)

Simple methods for the detection of keratan sulphate in urine have been applied to over 300 urine samples collected from children and adults with bone and cartilage dysplasias with or without mental retardation. Abnormal keratan sulphate excretion, which is a feature of type IV mucopolysaccharidosis (Morquio syndrome), is found in patients with that condition only during childhood. Abnormal excretion is also a feature of Kniest dysplasia and GM1 gangliosidosis and may be present in a number of other bone and cartilage dysplasias of unknown aetiology.
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PMID:Abnormal keratan sulphate excretion. 16 Feb 11

The mucopolysaccharidoses are genetic disorders of glycosaminoglycan metabolism. Patients with these diseases accumulate within the lysosomes of most tissues excessive amounts of dermatan and/or heparan sulfates, or of keratan sulfate. The clinical consequences of such glycosaminoglycan storage range from skeletal abnormalities to cardiovascular problems, and to motor and mental retardation. In all mucopolysaccharidoses, except Morquio disease, an excessive accumulation of sulfate-labeled glycosaminoglycans has been demonstrated in fibroblasts cultured from the patient's skin. It was subsequently shown that this was due to the deficiency of specific proteins which were named "corrective factors", because their addition to the culture medium effected a normalization of the impaired glycosaminoglycan catabolism in the respective mucopolysaccharidosis fibroblasts. The investigation of the function of the corrective factors, and other studies, led to the identification of the enzymatic defect in each of the mucopolysaccharidoses. Seven lysosomal enzyme deficiencies are now recognized among this group of disorders. A classification of the diseases, according to the mutant gene products, reveals that there is considerable phenotypic variation not only between diseases, but also within several disease types. With the availability of the appropriate enzyme assays, the previous difficulties in diagnosing these disorders have now been overcome. Methods are also available for the prenatal diagnosis, and the detection of heterozygous individuals, in most of the mucopolysaccharidoses. Although correction of the metabolic defect through enzyme replacement has been achieved in tissue culture, many problems remain to be solved before such therapy may become applicable in the patients themselves.
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PMID:The mucopolysaccharidoses: inborn errors of glycosaminoglycan catabolism. 82 Jun 26

Pathological type complications associated with 46 cases of neurofibromatosis in children under 12 are reported. It is noted that in 65.2% of the cases there are mental retardation, usually serious. More than 50% (24 cases) had some type of tumoration. All were benign with the exception of a suprarenal neuroblastoma that caused arterial hypertension and histological characteristics of malignancy. Fifteen tumors were located in the optica ways, one in the mediastinum, one in the abdomen, one in the paravertebral area, one which was a craneal plexiform tumor and four of the moluscum pendulum type on the eyelids or in neighbouring regions. Twelve children suffered from some type of seizures (Salaam's spasms, tonic-clonic, myoclonic, atonic and versive). Radiological abnormalities were very frequent in the simple X rays as well as in those in which contrast medium was used. In four cases malformations of the midline were observed, three of which were non-communicating cysts of the septum pellucidum, the other agenesis of the corpus callosum. Neurofibromatosis was further seen associated iwth Bourneville's syndrome, Morquio's syndrome, Batten's type of lipofuscinosis, facial or generalized hemihypertrophia and stenosis of the aqueduct. Heredity was dominant autosomic in 16 cases, the rest being due to possible recent mutations.
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PMID:[Pathological complications in 46 cases of neurofibromatosis in children (author's transl)]. 82 74

Cranial computed tomography (CT) was performed on 11 cases of mucopolysaccharidosis (MPS) IVA (Morquio syndrome). Our results suggest that although the patients may have normal intelligence CT changes may be seen with increasing age. In two cases white matter low density was found and in a third there was gross dilatation of the ventricles, basal cisterns and subarachnoid space. Nine other patients with various types of mucopolysaccharidosis also had cranial CT performed and in general those types associated with mental retardation showed changes although there was an interesting exception involving a case of MPS IIIA who had a normal CT scan.
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PMID:The value of computed tomography in patients with mucopolysaccharidosis. 312 17

Dyggve-Melchior-Clausen (DMC) is a rare autosomal-recessive disorder characterized by the association of a progressive spondylo-epi-metaphyseal dysplasia and mental retardation ranging from mild to severe. Electron microscopy studies of both DMC chondrocytes and fibroblasts reveal an enlarged endoplasmic reticulum network and a large number of intracytoplasmic membranous vesicles, suggesting that DMC syndrome may be a storage disorder. Indeed, DMC phenotype is often compared to that of type IV mucopolysaccharidosis (Morquio disease), a lysosomal disorder due to either N-acetylgalactosamine-6-sulphatase or beta-galactosidase deficiency. To date, however, the lysosomal pathway appears normal in DMC patients and biochemical analyses failed to reveal any enzymatic deficiency or accumulated substrate. Linkage studies using homozygosity mapping have led to the localization of the disease-causing gene on chromosome 18q21.1. The gene was recently identified as a novel transcript (Dym) encoding a 669-amino acid product (Dymeclin) with no known domains or function. Sixteen different Dym mutations have now been described in 21 unrelated families with at least five founder effects in Morocco, Lebanon, and Guam Island. Smith-MacCort syndrome (SMC), a rare variant of DMC syndrome without mental retardation, was shown to be allelic of DMC syndrome and to result from mutations in Dym that would be less deleterious to the brain. The present review focuses on clinical, radiological, and cellular features and evolution of DMC/SMC syndromes and discusses them with regard to identified Dym mutations and possible roles of the Dym gene product.
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PMID:Recent advances in Dyggve-Melchior-Clausen syndrome. 1546 20

Radiographic features of a 15-year-old boy with Smith-McCort dysplasia are presented. Dyggve-Melchior-Clausen syndrome without mental retardation has clinical and radiographic findings similar to those of Smith-McCort dysplasia. Both of these syndromes are rare autosomal recessive disorders affecting skeletal development. The radiographic appearance of generalized platyspondyly with double-humped end-plates, and the lace-like appearance of iliac crests are pathognomonic and distinctive of these syndromes. Diagnostic features of these diseases are compared with others like Morquio's disease and spondylometaphyseal dysplasia, which may have similar vertebral changes, and are discussed in the light of the literature.
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PMID:Dyggve-Melchior-Clausen syndrome without mental retardation (Smith-McCort dysplasia). 1620 59

Dyggve-Melchior-Clausen (DMC) syndrome is a rare autosomal recessive disorder characterized by the association of a progressive spondyloepimetaphyseal dysplasia and mental retardation ranging from mild to severe. The disorder results from mutations in the dymeclin (DYM) gene in the 18q12-12.1 chromosomal region. We report two siblings with classical clinical and radiological features of DMC and asymptomatic atlanto-axial dislocation. A novel homozygous splice-site mutation (IVS15+3G>T) was detected. Reverse transcriptase polymerase chain reaction (RT-PCR) confirmed that this mutation affects normal splicing. To the best of our knowledge, this is the first report of DMC from Saudi Arabia. The splice mutation noted in our patients was compared to the previously reported cases and supports the hypothesis that loss of DYM function is the likely mechanism of disease pathogenesis. In conclusion, distinction between this type of skeletal dysplasia and Morquio disease (MPS IV) is important for paediatricians and clinical geneticist in providing standard patient care and genetic counselling.
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PMID:Dyggve-Melchior-Clausen syndrome: novel splice mutation with atlanto-axial subluxation. 2086 80

Dyggve Melchior Clausen syndrome is a rare autosomal recessive disorder, characterized by progressive spondylo epi metaphyseal dysplasia associated with mental retardation. The clinical and radiological findings resembles Morquio disease at the onset of condition, which may hinder its diagnosis. Two siblings with chatacteristic clinical (progressive postnatal dwarfism and mental retardation) and radiological features (irregular lace-like appearance of the iliac crests) are reported.
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PMID:Dyggve melchior clausen syndrome. 2114 3

Skeletal dysplasias are a heterogeneous group of disorders characterized by an alteration of the organization of osseous tissue causing a distortion on the growth and development pattern of bones. In 1998, four Japanese sibs were described by the first time, three males and one female who presented a previously undescribed spondylo-epiphyseal dysplasia associated with craniosynostosis, cataracts, cleft palate and different grades of mental retardation. A probable autosomic recessive inheritance was suggested, but a germinal mosaicism could not be discarded. This is a case report of a patient with clinical and radiological findings similar to the ones previously described, born to second degree consanguineous parents. This supports the postulated presumption of a mutation with an autosomic recessive inheritance. The present communication represents the fifth case reported in the literature and the second familiar group affected.
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PMID:[Spondylo-epiphyseal dysplasia associated with craniosynostosis, cleft palate and mental retardation. A case report]. 2136 79

Type IVA mucopolysaccharidosis or Morquio A disease is a lysosomal storage disease, autosomal recessive, caused by deficiency of the N-acetylgalactosamine-6-sulfate sulfatase or GALNS. The severe phenotype is characterized by a severe skeletal dysplasia without any mental retardation. The aim of this study was to propose a strategy of molecular and prenatal diagnosis of this pathology. A molecular study was carried out on 7 patients MPS IVA issued from 5 unrelated families recruited from different Tunisian regions. All the patients were offspring of consanguineous marriages. The clinical and biologic study confirmed the diagnosis of MPS IVA within the 7 studied patients. Three GALNS mutations were identified by molecular analysis: IVS1+1G>A, G66R and A85T. The unions between Tunisian relatives are important and increase the Morquio A incidence in Tunisia. The identification of GALNS mutations in the Tunisian population permits better understanding of the Morquio A phenotype, a reliable genetic counselling and a molecular prenatal diagnosis to Tunisian at-risk relatives.
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PMID:[Morquio A disease: clinical and molecular study of Tunisian patients]. 2189 7


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