[Are there various forms of gyrate atrophy of the choroid and retina? (choroidal and retinal gyrate atrophy with and without ornithinemia)].
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Adult↗
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Gyrate atrophy of the choroid and retina with hyperornithinemia: tubular aggregates and type 2 fiber atrophy in muscle.
We studied 21 patients with gyrate atrophy of the choroid and retina and hyperornithinemia. Although the patients were not weak, type 2 muscle fibers were almost universally atrophic and had tubular aggregates. Gyrate atrophy is the first disease in which females are shown to have tubular aggregates; the sexes were affected equally. In gyrate atrophy the number of type 2 fibers decreases with age. The muscle and eye changes are probably related to abnormal creatine synthesis, caused, in gyrate atrophy, by the increased body pool of ornithine; muscle abnormalities may also be present in other tapetoretinal dystrophies.
Adolescent↗
A specific enzyme defect in gyrate atrophy.
To establish the enzyme defect in gyrate atrophy, we measured the activity of ornithine aminotransferase in phytohemagglutinin stimulated lymphocytes in a patient with gyrate atrophy, her daughter, and three normal controls. The patient's cells had no detectable ornithine aminotransferase activity and the daughter's cells had 44% of control activity. This intermediate value is characteristic of an obligate heterozygote. These results are the first demonstration of an enzyme defect in gyrate atrophy.
Adult↗
Ornithine ketoacid transaminase deficiency in gyrate atrophy of the choroid and retina.
Gyrate atrophy of the choroid and retina is a chorioretinal degeneration associated with hyperornithinemia with an autosomal recessive mode of inheritance. Cultured skin fibroblasts from five affected patients showed a virtual absence of ornithine ketoacid transaminase (OKT) (L-ornithine:2-oxoacid aminotransferase E.C.2.6.1.13) activity. Fibroblasts from four carrier parents showed a 42%-65% reduction in OKT activity. Increasing the concentration of pyridoxal phosphate (vitamin B6 in the assay media resulted in partial restoration of OKT activity in fibroblasts from one out of five patients studied. We conclude that OKT deficiency is closely associated with the genetic defect in gyrate atrophy of the choroid and retina and that genetic heterogeneity exists in this disease.
Adolescent↗
Gyrate atrophy of the choroid and retina: deficiency of ornithine aminotransferase in transformed lymphocytes.
Gyrate atrophy of the choroid and retina is an inherited form of chorioretinal degeneration associated with hyperornithinemia. We measured the activity of ornithine aminotransferase (L-ornithine:2-oxo-acid aminotransferase, EC 2.6.1.13) in phytohemagglutinin-stimulated lymphocytes of a patient with gyrate atrophy and her daughter. The patient's cells had no detectable ornithine aminotransferase activity, and the activity in the heterozygote's cells was 44% of normal values. Measurements of [3H]thymidine incorporation and other transformation-affected enzymes verified that the patient's cells were transformed. These results demonstrate an enzyme deficiency in gyrate atrophy.
Adult↗
Central gyrate atrophy: a case report.
Central gyrate atrophy is a rare ocular finding with a unique pathogenesis and fundus appearance. This entity results in total atrophy of the large and small vessels of the choroid and concomitant changes in the outer layers of the retina. A case report is presented to demonstrate the clinical appearance of this lesion and its relationship to the pathogenesis.
Adult↗
Ocular and biochemical abnormalities in gyrate atrophy of the choroid and retina.
Patients with gyrate atrophy of the choroid and retina have myopia, constricted visual fields, elevated dark adaptation thresholds, small or nondetectable ERGs, and chorioretinal atrophy. Biochemical abnormalities include hyperornithinemia, hypolysinemia, hyperornithinuria, an unknown amino compound in the urine, and virtual absence of OKT activity in extracts of cultured skin fibroblasts. Extracts of cultured skin fibroblasts from one patient studied in our laboratory showed an increase in OKT activity with increasing concentrations of vitamin B6 in the assay medium; this patient also showed some biochemical responsiveness within three weeks to 300 mg/day or orally administered vitamin B6. Three patients whose fibroblasts did not show increased OKT activity in vitro with increasing vitamin B6 did not respond in vivo to 300 mg/day of vitamin B6 over the same period. All four patients continue to be evaluated with larger doses of this vitamin. It remains to be established if long-term treatment with vitamin B6 will stabilize the course of the chorioretinal degeneration for at least some patients with this disease.
Administration, Oral↗
Gyrate atrophy of the choroid and retina with reticular pigmentary dystrophy and ornithine-ketoacid-transaminase deficiency.
A 10 year old white girl is presented with gyrate atrophy of the choroid and retina (atrofia gyrata). She also showed reticular pigmentations at the level of the retinal pigment epithelium temporal to both maculas. A generalized hyperornithinaemia was demonstrated in this patient and cultured fibroblasts established the underlying ornithine-keto-acid-transaminase (OKT) deficiency for the first time. Pharmacologic doses of vitamin B6 nor restriction of dietary protein resulted in a significant decrease of the serum ornithine concentration. It is probable that hyperornithinaemia in itself is not the cause of the gyrate atrophy.
Adult↗
Gyrate atrophy of the choroid and retina.
A case of gyrate atrophy of choroid and retina is presented. The serum level of ornithine was 788 mumol/l. The clinical features, the error of metabolism, the inheritance and the treatment of the disease are discussed.
Adolescent↗
Hyperornithinemia and gyrate atrophy of the choroid and retina.
The diagnosis of hyperornithinemia and gyrate atrophy (HOGA) depends upon the presence of five characteristic features: (1) typical chorioretinal lesions, (2) high myopia, (3) cataracts, (4) hyperornithinemia, and (5) autosomal recessive inheritance. We have seen three patients and described four new findings: (1) decreased whole blood glutamic acid, (2) low normal intelligence, (3) hepatic mitochondrial changes, and (4) urinary excretion of ornithine methyl ester. Investigations of amino acid metabolism in vivo are consistent with the presence of a defect in ornithine keto-acid transaminase.
Adult↗
Amino-acid metabolism and liver ultrastructure in hyperornithinemia with gyrate atrophy of the choroid and retina.
Three patients with the rare hyperornithinemia with gyrate atrophy of the choroid and retina (HOGA) syndrome were studied to elucidate the metabolic derangement and its pathologic concomitants. Tenfold elevations of blood ornithine levels, decreases in lysine levels, and hitherto unreported decreases in blood glutamate and glutamine concentration were observed. The output of ornithine from muscle kidney and splanchnic beds was curtailed or reversed after intravenous glucose. Levels of ornithine in venous blood declined after oral glucose, and rose after intravenous arginine. Increased amounts of 3-amino-2-piperidone were found in the urine, but these did not increase after the arginine-induced increase in ornithine levels. Liver biopsies in two patients revealed a marked alteration in mitochondrial ultrastructure. These studies extend the knowledge of the metabolic and pathologic derangements in HOGA. These findings are consistent with a disorder of ornithine-ketoacid transaminase, but such a disorder might not account for all the observations.
Adult↗
Hyperornithinemia and gyrate atrophy of choroid and retina. Report of a case.
A case of hyperornithinemia and gyrate atrophy of choroid and retina has been observed in a 3-year and 9-month-old girl. She presented also mild mental retardation, delayed language development and speech defects. The restriction of protein intake to a minimum of 0.8 g/kg/day induced a significant reduction of plasma ornithine levels. In some of the previous reports of the syndrome, a deficient ornithine-ketoacid transaminase activity has been found in cultured fibroblasts.
Atrophy↗
Gyrate atrophy of the retina: inborn error of L-ornithin:2-oxoacid aminotransferase.
Cultured fibroblasts from a patient with gyrate atrophy of the retina do not convert L-ornithine, uniformly labeled with carbon-14, to proline. This metabolic block is caused by deficient L-ornithine:2-oxoacid aminotransferase activity in the patient. Her heterozygote father has intermediate activity of this enzyme.
Adolescent↗
Metabolic studies in two families with hyperornithinemia and gyrate atrophy of choroid and retina.
Studies on the metabolism of selected amino acids were carried out in five patients with gyrate atrophy of the choroid and retina and four obligate heterozygotes. Hyperornithinemia, hyperornithinuria, and hypolysinemia were found in all patients. In one of the patients, the condition was diagnosed as early as 4 years of age. Ornithine loadings in the affected individuals did not induce the expected elevation of plasma glutamic acid and proline. Oral lysine tolerance tests in patients resulted in (1) enhancement of the hyperornithinuria and hyperlysinuria and (2) elevation of plasma lysine levels, which were below values obtained from normal controls. Supplementation of the regular diet with lysine for a period of 1 month increased plasma lysine but had no effect on plasma ornithine concentration.
Adolescent↗
Gyrate atrophy of choroid associated with hyperornithinaemia: report of the first case in Italy.
The first case in Italy and the youngest case in the world of gyrate atrophy of the choroid associated with hyperornithinaemia is reported. A therapeutical attempt has been made and the possibility of following the evolution of the ocular lesion is very interesting.
Adolescent↗
L-Ornithine-ketoacid-transaminase deficiency in cultured fibroblasts of a patient with hyperornithinaemia and gyrate atrophy of the choroid and retina.
L-Ornithine-ketoacid-transaminase deficiency was established in cultured fibroblasts obtained from a patient with hyperornithinaemia (mean ornithine level in serum approximately 100 mumol/l) and gyrate atrophy of the choroid and retina. The deficiency was found both the L-ornithine concentrations of 3.0 mM (about twice the KM value) and 12 mM, indicating that the enzymic defect was not due to a decreased affinity for this substrate. The reliability of the colorimetric assay of ornithine-ketoacid-transaminase activity was established radiochemically. Performance of the radiochemical assay revealed the presence of an impurity in the substrate DL-[2-14C]ornithine - HCl being a strong inhibitor of the enzyme. The passage level and the subcultivation time of the fibroblasts did not influence the enzymic activity.
Amino Acids↗
Deficient L-ornithine: 2-oxoacid aminotransferase activity in cultured fibroblasts from a patient with gyrate atrophy of the retina.
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Adolescent↗
Vitamin B6 in management of gyrate atrophy of choroid and retina.
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Administration, Oral↗