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Gyrate atrophy-like phenotype with normal plasma ornithine
U Kellner1, R G Weleber, N G Kennaway
1Freie Universität Berlin, Universitätsklinikum Benjamin Franklin, Augenklinik und Poliklinik, Germany.
Retina (Philadelphia, Pa.)
|January 1, 1997
Summary
Gyrate atrophy-like retinal disease can occur without ornithine deficiency. This suggests other genetic causes, potentially autosomal dominant inheritance, for this progressive vision loss.
Area of Science:
- Ophthalmology
- Medical Genetics
Background:
- Gyrate atrophy is a rare inherited eye disease characterized by progressive chorioretinal atrophy.
- It is typically caused by a deficiency in the enzyme ornithine-delta-aminotransferase (ODAT).
Observation:
- This study describes six male patients with a gyrate atrophy-like phenotype but normal plasma ornithine levels.
- Clinical examination revealed progressive chorioretinal atrophy, visual field defects, and reduced electroretinogram and electrooculogram responses.
- Fibroblast ODAT activity and kinetic properties were normal in all patients.
Findings:
- The clinical presentation mimicked gyrate atrophy, despite normal ornithine levels and enzyme activity.
- Affected individuals exhibited progressive visual impairment, ranging from reduced electrophysiological responses in younger patients to significant vision loss in older ones.
- A familial pattern in three males across two generations suggested autosomal dominant inheritance in some cases.
Implications:
- The findings indicate that a gyrate atrophy-like phenotype can arise from causes other than ODAT deficiency.
- This expands the differential diagnosis for progressive chorioretinal atrophy.
- Autosomal dominant inheritance should be considered in families presenting with this phenotype and normal ornithine metabolism.