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Muscle creatine phosphate in gyrate atrophy of the choroid and retina with hyperornithinaemia–clues to pathogenesis
Author(s) -
Kaarlo Heinänen,
Kirsti NäntöSalonen,
Markku Komu,
Minna Erkintalo,
Olli J. Hein,
Kari Pulkki,
Mika Valtonen,
Eeva Nikoskelainen,
A. Alanen,
Olli Simell
Publication year - 1999
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1046/j.1365-2362.1999.00467.x
Subject(s) - creatine , medicine , retinitis pigmentosa , endocrinology , pathogenesis , ornithine , atrophy , retina , biology , ophthalmology , retinal , biochemistry , arginine , amino acid , neuroscience
Background In gyrate atrophy of the choroid and retina with hyperornithinaemia (GA), inherited deficiency of ornithine‐δ‐aminotransferase leads to progressive fundus destruction and atrophy of type II skeletal muscle fibres. Because high ornithine concentrations inhibit creatine biosynthesis, the ensuing deficiency of high‐energy creatine phosphate may mediate the pathogenesis. Materials and methods Relative concentrations of inorganic phosphate (P i ), creatine phosphate (PCr) and ATP in resting calf muscle were recorded in 23 GA patients and 33 control subjects using 31 P‐magnetic resonance spectroscopy (MRS). Eight patients with autosomal recessive retinitis pigmentosa with matched control subjects constituted an additional reference group. Results The PCr/P i and PCr/ATP ratios (means ± SD) were lower for the GA patients than for healthy control subjects [4.66 ± 0.37 vs. 9.75 ± 2.17 ( P < 0.0001) and 2.85 ± 0.37 vs. 3.70 ± 0.50 ( P < 0.05) respectively]. In retinitis pigmentosa the respective values were 9.12 ± 2.57 and 4.25 ± 0.45. Age and stage of the disease had no effect. Conclusion Muscle 31 P‐MRS spectra were markedly abnormal in all GA patients.