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)

A 4.5-year-old male patient is described with chorioretinopathy, minor facial anomalies, delayed closure of the fontanel, mental retardation, moderate hypotonia, epilepsy and hepatic fibrosis. Postural control, intentional vocalising and manual dexterity were superior to the performance of patients with classical Zellweger syndrome (ZS). Morphologically distinct peroxisomes were absent in the liver. In blood elevated pipecolic acid levels and abnormal levels of bile acid intermediates were found. The plasmalogen content of erythrocytes was normal. In fibroblasts we found an accumulation of very long chain fatty acids, decreased activity of acyl CoA:dihydroxyacetone phosphate acyltransferase, and impaired de novo biosynthesis of plasmalogens. On the basis of these clinical, ultrastructural and biochemical characteristics we assume that this patient represents a milder variant of the classical cerebro-hepato-renal syndrome of Zellweger.
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PMID:A milder variant of Zellweger syndrome. 407 50

The cerebro-hepato-renal syndrome of Zellweger is an autosomal recessive inborn error of metabolism. Clinically the disease is characterised by craniofacial malformations, a lack of muscle tone, disturbances in liver function, renal cysts and mental retardation. The disease is characterised biochemically by the absence of peroxisomes (microbodies) in liver and kidney and variable abnormalities in mitochondria. This results in elevated concentrations of pipecolic acid and of tri(di)hydroxycoprostanoic acid in urine, CSF and/or duodenal fluid, an elevation of the concentration of very long chain (greater than C22) fatty acids in plasma and fibroblasts and a deficiency of plasmalogens in tissues, erythrocytes and fibroblasts. Moreover, we recently found that in Zellweger patients the activity of dihydroxyacetone phosphate acyltransferase is deficient in tissues, fibroblasts and cultured amniotic fluid cells and that the incorporation of a radioactive precursor of plasmalogens into phospholipids is impaired in fibroblasts and amniocytes. These recent findings allow specific prenatal and postnatal diagnosis of this disease.
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PMID:[Diagnosis of Zellweger's cerebrohepatorenal syndrome]. 652 20

Many cell surface proteins in mammalian cells are anchored to the plasma membrane via glycosylphosphatidylinositol (GPI). The predominant form of mammalian GPI contains 1-alkyl-2-acyl phosphatidylinositol (PI), which is generated by lipid remodeling from diacyl PI. The conversion of diacyl PI to 1-alkyl-2-acyl PI occurs in the ER at the third intermediate in the GPI biosynthetic pathway. This lipid remodeling requires the alkyl-phospholipid biosynthetic pathway in peroxisome. Indeed, cells defective in dihydroxyacetone phosphate acyltransferase (DHAP-AT) or alkyl-DHAP synthase express only the diacyl form of GPI-anchored proteins. A defect in the alkyl-phospholipid biosynthetic pathway causes a peroxisomal disorder, rhizomelic chondrodysplasia punctata (RCDP), and defective biogenesis of peroxisomes causes Zellweger syndrome, both of which are lethal genetic diseases with multiple clinical phenotypes such as psychomotor defects, mental retardation, and skeletal abnormalities. Here, we report that GPI lipid remodeling is defective in cells from patients with Zellweger syndrome having mutations in the peroxisomal biogenesis factors PEX5, PEX16, and PEX19 and in cells from patients with RCDP types 1, 2, and 3 caused by mutations in PEX7, DHAP-AT, and alkyl-DHAP synthase, respectively. Absence of the 1-alkyl-2-acyl form of GPI-anchored proteins might account for some of the complex phenotypes of these two major peroxisomal disorders.
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PMID:Defective lipid remodeling of GPI anchors in peroxisomal disorders, Zellweger syndrome, and rhizomelic chondrodysplasia punctata. 2225 71