Thompson, Dorothy A. and Lyons, Ruth J. and Liasis, Alki and Russell-Eggitt, Isabelle and Jaegle, Herbert and Gruenewald, Stephanie (2012) Retinal On-Pathway Deficit in Congenital Disorder of Glycosylation Due to Phosphomannomutase Deficiency. ARCHIVES OF OPHTHALMOLOGY, 130 (6). pp. 712-719. ISSN 0003-9950,
Full text not available from this repository. (Request a copy)Abstract
Objective: To describe novel electroretinographic (ERG) findings associated with congenital disorder of glycosylation due to phosphomannomutase deficiency (PMM2-CDG) (previously known as congenital disorder of glycosylation type 1a). Methods: Two male siblings with genetically confirmed PMM2-CDG underwent full-field ERG to a range of scotopic and photopic flash luminances that extended the International Society for Clinical Electrophysiology of Vision standard protocol and included scotopic 15-Hz flicker and photopic prolonged on-off stimulation. Results: Photopic prolonged ERGs were profoundly electronegative with absent b-waves but preserved oscillatory potentials. Prolonged off-responses and off-oscillatory potentials were preserved. Transient full-field photopic ERGs revealed a broad a-wave and narrow b-wave, and the photopic 30-Hz flicker ERG had a saw-tooth waveform. The scotopic b-waves of both cases were attenuated to the fifth percentile, whereas scotopic a-wave amplitudes were at the 50th to 75th percentile, giving a reduced a:b ratio. The scotopic a-wave waveform was well defined to bright flash luminance. The number of scotopic oscillatory potentials was preserved, although amplitudes were smaller than average. Scotopic 15-Hz flicker ERGs were evident to a range of flash luminances and showed an expected phase cancellation between -1.5 and -1.0 log scotopic td (troland) . s, but phase increased only for the fast rod pathway. Conclusions: We find, for the first time to our knowledge, an association of PMM2-CDG with a selective on-pathway dysfunction in the retina. This ERG phenotype localizes the site of retinal dysfunction to the on-bipolar synapse with photoreceptors. Modeling the unusual combination of ERG findings helps our understanding of the role of N-glycosylation at this synapse and provides a focus for future studies of potential intervention.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | STATIONARY NIGHT BLINDNESS; X-LINKED RETINOSCHISIS; GLYCOPROTEIN SYNDROME; BIPOLAR CELLS; NEGATIVE ELECTRORETINOGRAM; OSCILLATORY POTENTIALS; RETINITIS-PIGMENTOSA; MUSCULAR-DYSTROPHY; LIGHT RESPONSES; CA2+ CHANNELS; |
| Subjects: | 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Augenheilkunde |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 13 May 2020 04:58 |
| Last Modified: | 13 May 2020 04:58 |
| URI: | https://pred.uni-regensburg.de/id/eprint/18639 |
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