1/24. Characteristics of L-ornithine: 2-oxoacid aminotransferase and potential prenatal diagnosis of gyrate atrophy of the choroid and retina by first trimester chorionic villus sampling.A deficiency of the mitochondrial matrix enzyme L-ornithine: 2-oxoacid aminotransferase causes gyrate atrophy of the choroid and retina with hyperornithinemia (MIM 258870), a blinding degenerative disease, which is inherited as an autosomal recessive trait. We have developed a sensitive microradioisotopic method for enzyme assay by using 2-oxo-[5-14C] glutarate as the substrate and performing the separation of the product, [5-14C] glutamate from the substrate on a cation-exchange column. The enzyme activity was determined in human and rat tissues and in cultured cells. The enzyme activity in fibroblasts from a patient was deficient and that of the parents ranged between 25 and 60% of the control values. In addition we have found the enzyme expressed in native and cultured chorionic villi indicating a potential detection of the disease during the first trimester of pregnancy.- - - - - - - - - - ranking = 1keywords = atrophy (Clic here for more details about this article) |
2/24. Is it juvenile myoclonic epilepsy?A 21-year old man with marked developmental delay was referred for the diagnosis of myoclonic jerks (MJ), which were sometimes responsible for sudden falls without loss of consciousness, that had begun 2 years before, and for a recent generalized tonic-clonic seizure preceded by a cluster of MJ. physical examination revealed a small stature, bilateral pyramidal signs, severe mental retardation, and retinis pigmentosa. Etiological factors for this encephalopathy were not found (muscle and skin biopsies, karyotype and extensive blood chemistry). Waking interictal EEG showed a normal background activity and generalized poly-spike-and wave (PSW) discharges. photic stimulation disclosed a marked photoparoxysmal response, sometimes associated with myoclonic jerks. Three spontaneous jerks accompanied by a burst of generalized PSW were recorded on awakening from a nap. The MRI disclosed wide ventricles, a thin corpus callosum, brainstem atrophy and a so-called "redundant gyration"; these changes were evocative of acquired perinatal damage. Juvenile myoclonic epilepsy (JME) was diagnosed and valproate was started resulting in complete control of seizures. During a 5-year follow-up, the patient has remained seizure-free and the EEG consistently normal. In our opinion, JME can be diagnosed in very uncommon settings, including patients with significant brain damage, as long as all the other criteria for the diagnosis are present.- - - - - - - - - - ranking = 0.2keywords = atrophy (Clic here for more details about this article) |
3/24. Regional choroidal atrophy and alopecia. A new syndrome.Two siblings with total regional choroidal atrophy and other manifestations of ectodermal dysplasia are presented. The mode of inheritance is uncertain, but mild macular disease in the father may represent heterozygote manifestation of a recessive condition.- - - - - - - - - - ranking = 1keywords = atrophy (Clic here for more details about this article) |
4/24. Possible role of polyamines in gyrate atrophy.PURPOSE: gyrate atrophy (GA) is marked by hyperornithinemia and lowered ornithine amino transferase (OAT). However there are patients of GA without hyperornithinemia and those with hyperornithinemia without GA. Some cases of GA have been reported to have low lysine. The purpose of the study was to determine if polyamines, the metabolites of ornithine, and lysine have any diagnostic role in GA. methods: ornithine in plasma was estimated by two-dimensional paper chromatography, with elution of the coloured spot, and the absorbance measured using a spectrophotometer at 560 nm. OAT assay in lymphocytes was done spectrophotometrically using ornithine as substrate. blood and urinary polyamines were extracted with n-butanol, benzoylated and analysed with HPLC; putrescine, spermine, spermidine, and cadaverine were assayed individually at 254 nm with the UV detector using ODS, G18 column with 63% methanol as solvent. RESULTS: Of the 7 patients investigated, 6 had features typical of GA. One was diagnosed to have atypical retinitis pigmentosa (case 3). The first five cases had elevated ornithine and diminished OAT, but cases 6 and 7 had near-normal ornithine and case 7 had near-normal OAT. However, all 7 patients had increased levels of total polyamines in urine compared to normals. Five had increased putrescine and three had increased spermine. All the 7 had decreased cadaverine in urine. Thus, though there were inconsistencies with ornithine and OAT, all the 7 patients had elevated polyamines from ornithine and decreased cadaverine. CONCLUSION: In addition to estimating ornithine and OAT in GA, it is suggested that urinary polyamines may be analysed as the latter appears to correlate better with the clinical condition and help in the diagnosis to a greater extent. Moreover, while ornithine is an innocuous amino acid, polyamines are known to damage dna and proteins.- - - - - - - - - - ranking = 1keywords = atrophy (Clic here for more details about this article) |
5/24. gyrate atrophy of the choroid and retina: further experience with long-term reduction of ornithine levels in children.OBJECTIVE: To determine whether the long-term reduction of plasma ornithine levels by way of an arginine-restricted diet in patients with gyrate atrophy will slow the progression of this chorioretinal degeneration. DESIGN: natural history study of 2 pairs of siblings with gyrate atrophy treated with an arginine-restricted diet. MAIN OUTCOME MEASURES: Fundus photography and electrophysical and psychophysical retinal function tests. RESULTS: After 16 to 17 years of receiving an arginine-restricted diet, the younger sibling in each pair, who was prescribed the diet at an earlier age than the older sibling, demonstrated a slower progression of lesions compared with the older sibling. CONCLUSIONS: If started at an early age, long-term substantial reduction of plasma ornithine levels may appreciably slow the progression of the chorioretinal lesions and, to a lesser extent, the progressive loss of retinal function in patients with gyrate atrophy.- - - - - - - - - - ranking = 1.4keywords = atrophy (Clic here for more details about this article) |
6/24. gyrate atrophy of choroid and retina.gyrate atrophy of choroid and retina is a rare disorder of autosomal recessive nature. There occurs patchy and progressive atrophy of the choroid and retina at the equatorial region with central area being less affected. Here in this case report, one woman of about 47 years attended at the retina clinic, Tenennt Institute of ophthalmology, Glasgow University with the history of gradual loss of vision. On fundus examination, sharply defined bizarre shaped atrophic areas of fundus was seen in both the eyes. Velvet like fine granular pigments were present in the macula, the zone of healthy retina and the periphery. The colourless, elongated, glittering crystals were scattered over the dark brown pigments visible through 90 dioptre lens. Bone corpuscles pigments were not found. fluorescein angiography showed hyperfluorescence in the area of gyrate atrophy. Her plasma ornithine level and plasma tiramine level were 1 90 U mol/l and 357 U mol/l. respectively. A rigid schedule of low protein diet including near total elimination of arginine with supplementation of essential amino acids was advised since the diagnosis was established.- - - - - - - - - - ranking = 1.4keywords = atrophy (Clic here for more details about this article) |
7/24. gyrate atrophy of the choroid: two cases.INTRODUCTION: gyrate atrophy of the choroid (GA) is a rare, inherited choroidal dystrophy that results in progressive deterioration in peripheral and night vision. This is the first documentation of GA in singapore. CLINICAL PICTURE: This report illustrates 2 cases of a sibling pair from a consanguineous union, presenting with the classical clinical features and biochemical abnormality of this condition. TREATMENT AND OUTCOME: One patient was treated with pyridoxine replacement and a low protein diet. However, his condition failed to improve. The other patient was left untreated. CONCLUSION: Treatment was ineffective for the first patient. As yet, there is no proven treatment of GA.- - - - - - - - - - ranking = 1keywords = atrophy (Clic here for more details about this article) |
8/24. A 15-bp deletion in exon 5 of the ornithine aminotransferase (OAT) locus associated with gyrate atrophy.gyrate atrophy of the choroid and retina (GA) is an autosomal recessive disorder in which a deficiency of the mitochondrial matrix enzyme ornithine aminotransferase (OAT) leads to progressive blindness. Previously, we and others have reported a number of missense mutations and splice defects in the OAT gene associated with GA. In the present case, through sequencing of the PCR amplified cDNA products, we have detected a novel 15-bp deletion within exon 5 of the OAT gene which retains the original reading frame. The deleted PCR product is the only one produced from the patient's mRNA, while mRNA from the patient's mother yields both deleted and normal length PCR products. The alternate, apparently nonexpressing OAT allele in this patient was inherited from the father, who displays only the normal length PCR product. The codon at the deletion joint remains unaltered, predicting the loss of the pentapeptide Tyr-Thr-Val-Lys-Gly without any other amino acid change. The breakpoints are adjacent to or within two copies of a 4-bp direct repeat, which may have implications for the mechanism of deletion.- - - - - - - - - - ranking = 1keywords = atrophy (Clic here for more details about this article) |
9/24. Anterior subcapsular plaque cataract in hyperornithinaemia gyrate atrophy--a case report.Hyperornithinaemia gyrate atrophy (HOGA) is a rare autosomal recessive disorder in which chorioretinal degeneration occurs with cataracts, myopia, and hyperornithinaemia. We report the case of an 18-year-old female who presented with the typical features of HOGA, including posterior subcapsular cataracts and elevated plasma ornithine. She later developed distorted vision in both eyes owing to wrinkling of the anterior lens capsules. Histological examination following lens extraction showed the wrinkling was caused by focal distortion from capsular fibrosis (anterior subcapsular plaque cataract). This specific lens change has not been linked previously with HOGA.- - - - - - - - - - ranking = 1keywords = atrophy (Clic here for more details about this article) |
10/24. Low-protein diet and progression of retinal degeneration in gyrate atrophy of the choroid and retina: a twenty-six-year follow-up.gyrate atrophy of the choroid and retina is an autosomal recessive chorioretinal dystrophy which leads to a slowly progressive loss of vision. The primary defect is due to a deficiency of the enzyme ornithine delta-aminotransferase, which is responsible for markedly elevated levels of ornithine in plasma and other body fluids. Although several therapeutic regimens have been proposed, the reduction in ornithine accumulation obtained by reducing the intake of its precursor arginine (semisynthetic low-arginine diet) is the one most practised. In this clinical and molecular study we report a patient with hyperornithinaemia and gyrate atrophy of the choroid and retina who had been diagnosed when she was 3 years 9 months old. She also presented mild mental retardation, delayed language development and speech defects. The patient has recently been found to be homozygous for the new Gly91Arg amino acid substitution of the enzyme ornithine delta-aminotransferase. This mutation lies in a region of the mature protein that is considered crucial for the mitochondrial targeting activity. In this patient, a 28-year treatment with a completely natural low-protein diet (0.8 g/kg per day of natural protein) has been able to significantly reduce ornithine plasma levels, and to greatly delay the natural progression of the chorioretinal changes. This study suggests that, in the long-term treatment of gyrate atrophy, the efficacy in slowing the progression of chorioretinal changes and the palatability of a completely natural low-protein diet make this treatment a potentially viable alternative in patients refusing the semisynthetic diet.- - - - - - - - - - ranking = 1.4keywords = atrophy (Clic here for more details about this article) |
| | Next -> |