Muscle creatine phosphate in gyrate atrophy of the choroid and retina with hyperornithinaemia--clues to pathogenesis

: Heinänen K, Näntö-Salonen K, Komu M, Erkintalo M, Heinonen OJ, Pulkki K, Valtonen M, Nikoskelainen E, Alanen A, Simell O

: 1999

: European Journal of Clinical Investigation

: European journal of clinical investigation

: Eur J Clin Invest

: 29

: 5

: 426

: 31

: 6

: 0014-2972

In gyrate atrophy of the choroid and retina with hyperornithinaemia (GA), inherited deficiency of ornithine-o-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.\nRelative concentrations of inorganic phosphate (Pi), creatine phosphate (PCr) and ATP in resting calf muscle were recorded in 23 GA patients and 33 control subjects using 31P-magnetic resonance spectroscopy (MRS). Eight patients with autosomal recessive retinitis pigmentosa with matched control subjects constituted an additional reference group.\nThe PCr/Pi 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.\nMuscle 31P-MRS spectra were markedly abnormal in all GA patients.\nBACKGROUND\nMATERIALS AND METHODS\nRESULTS\nCONCLUSION