The inheritance of the autosomal recessive type of gyrate atrophy of the choroid and retina seems well documented (Botermans, I 972), but the aetiology of the disease is still unknown.Animal experiments and some disturbances of lipid, carbohydrate, and protein metabolism connected with chorio-retinal degenerations in man support the possibility of an enzymatic disorder as an aetiological factor of these diseases (Franceschetti, Fran §ois, and Babel, I963; FranSois, I964).The present author recently diagnosed gyrate atrophy of the choroid and retina in an 8-year-old boy in whom an enlarged lysine-ornithine spot was found on the urine highvoltage electrophorogram in routine examination of urinary amino-acids. Further studies identified that the spot was ornithine. The plasma ornithine concentration was more than ten times higher than normal, although normal amounts of the other plasma aminoacids were present. A constant correlation between hyperornithinaemia and gyrate atrophy of the choroid and retina was then detected in nine other patients (Simell and Takki, I973).The purpose of this paper is to describe the different forms of gyrate atrophy found in a total of fifteen patients and to discuss the correlation of fundus changes with hyperornithinaemia. MaterialAn examination of case histories from I950 to 1972, with clinical diagnosis of any primary chorioretinal degeneration, revealed some thirty cases in which gyrate atrophy was suspected. Among them eleven cases of gyrate atrophy of the choroid and retina at different stages were found. Three additional cases were found among relatives of one patient and one further case was referred to the author. The total number of cases with gyrate atrophy of the choroid and retina described in this paper is thus fifteen, nine of which were included in our previous paper (Simell and Takki, I973). The characteristics of the patients are shown in Table I (overleaf). Among the ten families there were four sisters (Patients 6 and 9-I I) and two pairs of sisters (Patients 3, 5, and I 2-I3) and one of these was the first cousin of another patient (Patient 4).There were twenty intact and ten aphakic eyes, four of which were treated because of open-angle glaucoma. One eye was in postoperative phthisis after a cataract operation (Table II, overleaf).
The relative importance of genetic degenerative eye lesions as causes of blindness or impaired vision has increased because of the lack of effective treatment for such conditions as compared with other diseases. Related to the large and not very well-defined group of degenerative eye lesions termed tapeto-retinal degenerations, is a choroidal form known as gyrate atrophy of the choroid and retina.Night blindness is the most important subjective symptom in hereditary tapeto-retinal degeneration. Sharply-defined chorio-retinal atrophic areas of the fundus are typical of gyrate atrophy. In addition to constriction of the fields of vision, myopia, and complicated cataract, abnormalities in the electroretinogram, electro-oculogram, and fluorescein angiograms of the fundus form the basis for diagnosis.A constant relationship between gyrate atrophy of the choroid and retina and massively increased plasma ornithine concentration was found in our earlier studies (Simell and Takki, 1973; Takki, I974), in which it was suggested that the clinical symptoms and signs of the disease were due to large concentrations of ornithine in the plasma, aqueous humour, and cerebrospinal fluid or directly to the causative enzyme defect.Though gyrate atrophy of the choroid and retina is a relatively rare ophthalmological disease and the published series of patients are small, inheritance has been suggested. Con Kurstjens, I965;Rieger, 1972;Botermans, 1972), but autosomal inheritance now seems to be a probable cause (Kurstjens, I965; Botermans, I972). The combination ofclinical symptoms with inborn errors of metabolism was not understood until some relatives of the propositi were found to have the metabolic abnormality without the clinical disease (Ghadimi, Partington, and Hunter, I 96 I; Woody, Hutzler, and Dancis, I 966; Auerbach, DiGeorge, and Carpenter, I967). The aim of this work was to confirm the regular combination of massively increased plasma ornithine concentration with the ophthalmological symptoms and signs by studying the eyes and plasma and/or urinary amino-acids of relatives of the patients, to test the autosomal recessive mode of inheritance in this group of families, and to find a clinical method for heterozygote detection in hyperornithinaemia by studying ornithine metabolism in probable heterozygotes of the disease and in controls.
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