Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0917816 (mental retardation)
 15,867 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The metabolism of ground substance in connective tissue of an 18-year-old boy with oculo-cerebro-renal syndrome was studied. He had characteristic clinical and laboratory findings described by Lowe et al. such as growth retardation, mental deficiency, glaucoma, cataracta, decreased muscle tone, metabolic acidosis, aminoaciduria and osteomalacia. The urinary excretion of acid glycosaminoglycans and of total hydroxyproline were 27 mg/day (as glucuronic acid) and 280 mg/day respectively on admission. Both values decreased to the upper limits of normal level transiently during treatment with alkali and vitamin D2. At that time, an improvement in bone abnormalities, a decrease of serum alkaline phosphatase, and an elevation of serum inorganic phosphate were observed. The therapy prevented him from progressive osteomalacia and cured him of it, but mucopolysacchariduria and hydroxyprolinuria did not disappear. Analytical electrophoresis on cellulose acetate sheets showed that urinary acid glycosaminoglycans were composed of undersulfated chondroitin 4-/6-sulfate and heparan sulfate with a ratio of 6:4, on admission. After oral administration of alkali, the excretion of heparan sulfate decreased and undersulfated chondroitin 4-/6-sulfate was determined as a main component of urinary acid glycosaminoglycans. The clinical and laboratory data in this case suggested that the increased excretion of acid glycosaminoglycans and total hydroxyproline was caused by abnormal metabolism in connective tissues, especially by the bone abnormalities, in this syndrome.
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PMID:Urinary excretion of acid glycosaminoglycans and hydroxyproline in a patient with oculo-cerebro-renal syndrome. 73 46

Case report of a 18 year old boy with short stature, microceophaly, mental retardation and multiple dysmorphic signs. At the age of 9 years a severe generalised osteoporosis was discovered. A pathological fracture of the greenwoor type healed without proper callus formation. The osteoporosis persists without signs of either deterioration or improvement. The serum phosphorus is slightly decreased, while serum calcium, alkaline phosphatase and renal functions are normal. The main biochemical finding is a constant hyperclaciuria of 6-13 mg/kg/24 h, which can be corrected by treatment with oral sodium phosphate. No other chronic disease could be found which would explain the bone disease. The complex disease of this boy does not fit into the known pictures of osteogenesis imperfecta, idiopathic juvenile osteoporosis or of idiopathic hypercalciuria, and might therefore be another type of demineralising bone disease. It is suggested, that the cause might be an impairment of the calcium fixation of collagen fibres during desmal ossification.
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PMID:[Uncommon form of idiopathic osteoporosis with hypercalciuria, growth retardation and mental retardation]. 115 69

We report a case of HAM/TSP presenting with short stature, mental retardation, skin eruptions, uterine and ovarian hypogenesis and nephropathy. Skin erythema was noted since from the age of three years old and spasticity of lower extremities from elementary school age. Serum calcium level showed 4.1 mEq/l. Recombinant human PTH infusion resulted in no response of phosphate excretion. The persistent proteinuria prompted renal needle biopsy, which revealed IgA and C1q deposits in glomerular mesangium. A diagnosis of pseudohypoparathyroidism and IgA nephropathy was entertained. This patient with pseudohypoparathyroidism who has a deficient immune system was seized with the early onset of HAM/TSP and IgA nephropathy.
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PMID:A case of HTLV-I-associated myelopathy with IgA nephropathy and pseudohypoparathyroidism type 1. 179 21

In 1930 adenosine triphosphate appeared in the literature from W. A. Engelhardt's work on avian erythrocytes. This was an early example of oxidative phosphorylation in intact cells, and it required methylene blue and oxygen. Both Belitser and I realized that the use of Warburg manometers for aeration was critical in order to generate oxidative phosphorylation of glucose in tissue preparations. Test tube techniques did not work. In 1956 we were able to describe a human type of diabetes called "galactose diabetes," in which consumption of human or cows' milk provokes mental retardation. Replacement of human or cows' milk products with "vegetable milk" formula in early infancy can prevent retardation. We determined that the disease results from a defect of galactose-one-phosphate uridylyl-transferase, a hereditary enzyme. This type of enzyme defect, if discovered and treated in early infancy, is a benign molecular disease. Regulation of transport systems in mammalian cell cultures are frequently complex energized systems. Perhaps my greatest surprise in this regard was the mere fact that an all-cis "odd" hexose-D-allose turned out to be a highly intense down-regulator of the hexose transport system. Additions of inhibitors of oxidative phosphorylation (such as oligomycin or di-nitrophenol) arrested the allose-mediated down-regulation. We have reason to suspect that the strong down-regulator is a phosphorylated form of D-allose. Thus ends my story about oxidative energized biological phosphorylation systems.
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PMID:50 years of biological research--from oxidative phosphorylation to energy requiring transport regulation. 188 94

We describe the molecular characterization of two mutations responsible for galactosemia, an inherited disorder of galatose metabolism that causes jaundice, cataracts, and mental retardation in humans. The coding region of galactose-1-phosphate uridylyltransferase (GALT; UDPglucose:alpha-D-galactose-1-phosphate uridylyltransferase, EC 2.7.7.12) was amplified by the polymerase chain reaction from total cDNA of a classic galactosemic individual and was characterized by direct sequencing of the products. Two missense mutations were identified: (i) replacement of valine-44 by methionine and (ii) replacement of methionine-142 by lysine. These mutations led to a drastic reduction in GALT activity when individual mutant cDNAs were overexpressed in a mammalian cell system, although full-length protein is synthesized in this assay. The two galactosemia mutations account for 3 of the 15 galactosemia alleles analyzed. These results suggest that galactosemia is caused by a variety of mutations, which might be responsible for the observed clinical heterogeneity of this disorder. We also present the molecular characterization of two GALT polymorphisms: (i) replacement of leucine-62 by methionine and (ii) replacement of asparagine-314 by aspartate. It appears that galactosemia mutations tend to occur in regions that are highly conserved throughout evolution while the polymorphisms change variable residues.
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PMID:Molecular basis of galactosemia: mutations and polymorphisms in the gene encoding human galactose-1-phosphate uridylyltransferase. 201 74

Morphological changes are shown in the muscle biopsy specimens of an 8-year-old girl who suffered from a triosephosphate isomerase (TPI) deficiency, resulting in a chronic, nonspherocytic, hemolytic anemia, mental retardation and neuromuscular impairment. The newly introduced enzyme histochemical reaction for TPI demonstrated a total lack of histochemically detectable enzyme activity, whereas biochemical analysis of muscle tissue revealed less than 10% of the normal enzyme activity. Electron microscopy showed a degenerative myopathy with an increase in the amount of intracellular glycogen. Additionally, mitochondrial changes within the muscle fibers were observed to be similar to those in mitochondrial myopathies. The disturbed balance between glycerin-aldehyde phosphate and dihydroxyacetone phosphate, due to the deficiency of the TPI enzyme, is interpreted as the biochemical background of an impaired electron transport across the mitochondrial membrane, resulting in the coexistence of an impaired glycolytic pathway and an impaired mitochondrial metabolism of muscle cells.
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PMID:Myopathy with altered mitochondria due to a triosephosphate isomerase (TPI) deficiency. 233 91

Lowe (oculocerebrorenal) syndrome (LS) is an X-linked disorder characterized by congenital cataracts, generalized hypotonia, mental retardation, and renal Fanconi syndrome. The basic defect remains unknown, but the possibility that fibroblasts express reduced sulfation of glycosaminoglycans has been studied in several laboratories. A mechanism involving overproduction of an enzyme (nucleotide pyrophosphatase) active against adenosine 3'-phosphate, 5'-phosphosulfate (PAPS) has been postulated. Decreased synthesis of normally sulfated glycosaminoglycans was also reported. We measured the synthesis of proteoglycans and glycosaminoglycans by incorporation of [3H]glucosamine and Na2(35)SO4 into cultured fibroblasts from four LS patients and related it directly to the synthesis in six normal fibroblast cultures. We found that the rate of synthesis varied greatly among the normal cultures (cv, 30%), but not significantly between LS and the normal. The LS fibroblasts' ability to sulfate glycosaminoglycans was assayed as the amount of 3H-glycosaminoglycan eluting at low ionic strength on anion exchange chromatography, the amount of non-sulfated disaccharide present in chondroitinase digests of labeled proteoglycans, and the ratio of 35S to 3H incorporation into proteoglycans. Each parameter suggested that the LS cells were synthesizing normally sulfated glycosaminoglycans (e.g. % delta Di-0S, 21 +/- 6 in normal; 27 +/- 6 in LS). The cells' ability to sulfate glycosaminoglycans was tested under conditions of markedly stimulated glycosaminoglycan synthesis, by treating the cultures with a beta-D-xyloside. LS and normal cells responded to the treatment by elevating the rate of synthesis of normally sulfated glycosaminoglycans (3.5-6-fold in normal, 3-7-fold in LS). Nucleotide pyrophosphatase activities were found to be elevated in each of our four LS cell strains as in the previous studies, excluding genetic heterogeneity as an explanation for our findings. We conclude that LS fibroblasts do not express defects in sulfation of glycosaminoglycans or in synthesis of proteoglycans.
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PMID:Proteoglycan synthesis in normal and Lowe syndrome fibroblasts. 357 Dec 27

The authors report a new form of metaphyseal chondrodysplasia revealed in a 5 1/2 year-old boy with seizures. This disorder associated coxa vara, large terminal phalanges, bilateral cataracts and severe mental deficiency. Both parents were healthy, suggesting autosomal recessive transmission. There is no associated calcium phosphate metabolism disorder. An enzymatic abnormality might be the cause of the bone, ocular and neuronal lesions.
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PMID:[A new form of metaphyseal chondrodysplasia]. 357 65

A five-year-old girl was referred to prometaphase chromosome analysis because of mental retardation, facial dysmorphic features suggestive of Cornelia de Lange syndrome, cleft palate and additional minor congenital malformations of the cardiac system and fingers and toes. A familial balanced translocation (3;9)(q26.1; p23) was found. The karyotype of the proposita was 46,XX,der(9),t(3;9)(q26.1;p23). Thus the patient was trisomic for 3q26.1-qter and monosomic for 9p23-pter. The unbalanced chromosome constitution was not detected by standard Q-banding analysis shortly after birth. The karyotype was misdiagnosed as 46,XX,9(p+) in the proposita and her mother, and thought to be a normal variant of chromosome 9. The repeated cytogenetic study led to the diagnosis of the translocation and to the possibility of prenatal diagnosis in the translocation carriers. A survey of 22 published cases of dup(3q) showed that nearly 60% were secondary to familial balanced rearrangements with an excess of maternally derived abnormal chromosomes 3. Red blood cell galactose-1-phosphate-uridyltransferase (GALT) activity was normal in the patient, consistent with previous assignment of the gene locus for GALT to 9p13 (Shih et al. 1982).
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PMID:Partial trisomy 3q syndrome inherited from familial t(3;9)(q26.1; p23). 365 93

Three cases of pseudohypoparathyroidism with roentgenographic evidence of hyperparathyroid bone disease are described. Renal resistance to exogenous parathyroid hormone (PTH), the hallmark of pseudohypoparathyroidism, was documented by markedly blunted or absent urinary phosphate and cyclic AMP responses to parathyroid extract. At the time of diagnosis all patients were hypocalcemic and hyperphosphatemic with elevated serum alkaline phosphatase levels and subperiosteal resorption noted on skeletal films. Bone biopsy in one patient revealed a histologic appearance consistent with hyperparathyroidism. Serum PTH levels, measured in two patients while they were hypocalcemic, were elevated. None of the patients had short stature, brachydactyly, subcutaneous calcification or mental deficiency. These cases are compared to the 15 well-documented cases previously reported. The presently available information on pseudohypoparathyroidism indicates a variable skeletal response to PTH mediated by several factors extrinsic to bone and suggests that pseudohypoparathyroidism with hyperparathyroid bone disease is one extreme of a clinical spectrum of skeletal responsiveness to PTH. This disorder is part of an expanding clinical picture which makes pseudohypoparathyroidism a diagnostic consideration in any patient with unexplained hypocalcemia, hyperphosphatemia, elevated alkaline phosphatase levels or metabolic bone disease.
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PMID:Skeletal responsiveness in pseudohypoparathyroidism. A spectrum of clinical disease. 624


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