Ilkka Sipila

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Deficiency of ornithine–δ–aminotransferase (OAT) in humans causes hyperornithinaemia and gyrate atrophy (GA), a blinding chorioretinal degeneration. Surprisingly, OAT–deficient mice produced by gene targeting exhibit neonatal hypoornithinaemia and lethality, rescuable by short–term arginine supplementation. Post–weaning, these mice develop(More)
Deficiency of ornithine-delta-aminotransferase (OAT) in humans causes hyperornithinaemia and gyrate atrophy (GA), a blinding chorioretinal degeneration. Surprisingly, OAT-deficient mice produced by gene targeting exhibit neonatal hypoornithinaemia and lethality, rescuable by short-term arginine supplementation. Post-weaning, these mice develop(More)
Linear growth is more often impaired after liver than after renal transplantation (Tx) in childhood. As similar triple immunosuppression was used in our liver and renal transplant recipients, we were able to compare growth and endocrine function between 19 prepubertal liver and 35 renal transplant recipients. There were no significant differences in median(More)
Ornithine delta-aminotransferase is a nuclear-encoded mitochondrial matrix enzyme which catalyzes the reversible interconversion of ornithine and alpha-ketoglutarate to glutamate semialdehyde and glutamate. Inherited deficiency of ornithine delta-aminotransferase results in ornithine accumulation and a characteristic chorioretinal degeneration, gyrate(More)
Gyrate atrophy of the choroid and retina (GA) is an inherited chorioretinal degeneration caused by deficiency of ornithine delta-aminotransferase (OAT; L-ornithine: 2-oxo-acid aminotransferase; EC 2.6.1.13). GA is one of the "Finnish genetic diseases," a group of several rare monogenic disorders that occur with increased frequency in the Finnish population.(More)
BACKGROUND GH may improve phosphate balance and height in X-linked hypophosphatemic rickets (XLH). This study evaluated the impact of exclusive rhGH therapy on phosphate homeostasis and growth. METHODS Ten children (median age 12.2 years) with XLH were included in a 12-month trial with GH. Conventional treatment was discontinued 1 month prior GH (0.033(More)
GA is an autosomal recessive disorder with characteristic chorioretinal degeneration; atrophy and tubular aggregates in type II muscle fibers; 10-20 fold increase in ornithine concentration in body fluids; and deficient activity of ornithine-δ-aminotransferase. Based on the inhibition by high ornithine concentration of the rate-limiting enzyme of creatine(More)
GH provocative testing does not predict subsequent growth response, and is not therefore required before initiation of rhGH treatment in children with renal and liver transplants. However, therapeutic doses of glucocorticoids may potentially inhibit GH secretion in some patients, and determining GH secretory status by provocation tests and measuring(More)
GA patients exhibit chorioretinal degeneration and histologic muscle abnormalities. Owing to an inherited deficiency of ornithine aminotransferase, they accumulate ornithine to levels which are 10× normal and well above the Ki of glycine transamidinase, the first enzyme in the creatine biosynthetic pathway. Previous work utilizing an insensitive assay has(More)
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