97th DOG Annual Meeting 1999
PIGMENTARY RETINOPATHY AS A PRESENTING SIGN OF MITOCHONDRIAL ENCEPHALOMYOPATHY WITHOUT EXTERNAL OPHTALMOPLEGIA
S. Staudt1, A. M. Joussen1, D. Rating2, F. Wilichowski3, G. Kolling1, F. G. Holz1
Mitochondrial encephalomyopathies represent a genetically and biochemically heterogeneous group of diseases usually resulting from sporadic deletions of the mitochondrial (mt)DNA. Chronic progressive external ophtalmoplegia (CPEO) is a main sign of Kearns-Sayre syndrom (KSS). Herein, we describe a patient with structural mtDNA-aberration who presented with diffuse retinal changes in absence of impairment of ocular motility.
Patient and methods: A 7 year-old girl with pigmentary retinopathy was examined including electrophysiology, neuropediatrics, neuroradiology and ENT. mtDNA was isolated and analyzed by moleculargenetic techniques.
Results: Best vision was 0.4 OD and 0.5 OS without subjective progressive visual loss. Funduscopy disclosed bilateral widespread hyperpigmentations and adjacent depigmentations. The pigmentary retinopathy was also compatible with rubella retinopathy. Scotopic and multifocal electroretinogram were abnormal. Further signs included an incomplete inner ear deafness, ataxia, lapses of coordination and an intentional tremor. Compared with her twin sister the patient's speach was less modulated and slower. On MRI scan symmetric changes of density in the basalganglia and nucleus dentatus as well as in the brainstam were observed. ECG yielded no evidence of an AV-node-block. DNA-analysis showed a structural rearrangement with loss of ca. 8500 bp in the distal 2/3 of the mitochondrial genome between the origins of replication OL, OH. The proportion of mutant DNA was approximately 70%, proportion of wildtype DNA 30% (heteroplasmy).
Conclusions: The case demonstrates that mitochondrial encephalomyopathies in early stages may present with pronounced retinal changes in absence of external ophtalmoplegia. Therefore, it appears prudent to include a neuropediatric evaluation as well as a deletion screening of the mtDNA in the work-up of pediatric patients with diffuse nonspecific pigmentary retinopathies.
1Department of Ophthalmology, University of Heidelberg, Im Neuenheimer Feld 400, D-69120 Heidelberg
2Department of Pediatric Neurology, Im Neuenheimer Feld 150, D-69120 Heidelberg
3Department of Pediatrics, University of Göttingen, Robert-Koch-Str. 40, D-37075 Göttingen