Abstract
Purpose: :
Patients with Goldmann-Favre syndrome carry mutations in the NR2E3 gene. This gene codes for a photoreceptor-specific nuclear receptor. The present study aimed to analyze the distribution of rods, cones, and the red/green and blue opsins in the eyes of a donor with Goldmann-Favre syndrome. The patient was 88 years-old at the time of his dearth. His clinical phenotype, including an early history of night blindness, peripheral retinoschisis and midpheripheral plumpling of pigment were characteristic of the Goldmann-Favre syndrome. He was found to have a homozygous splice site mutation in the NR2E3 gene.
Methods: :
The affected eye was fixed in 4% paraformaldehyde and 0.5% glutaraldehyde in phosphate buffer. A perimacular area was cut and processed for transmission electron microscopy (TEM). Alternatively, cryostat tissue sections of the macula and periphery were studied by indirect immunofluorescence, using well-characterized monoclonal antibodies to the rhodopsin (mAb B630N), cone cytoplasm (mAb 7G6) and polyclonal antibodies to either red/green (AB5405) and blue (AB5407) opsins. The affected donor eye was compared to a matched normal eye.
Results: :
The retina was highly disorganized with indistinct layers. Bone spicule pigment was observed both in the perimacular and periphery of the eye. The RPE layer was discontinuous in some regions of the perimacula. Large (>1 micometer) spherical electrondense melanosomes were observed in the RPE and choroid by TEM. Rods were virtually absent in the affected retina. Cones were present in the macula, but were mostly absent from the retinal periphery. In addition, rosettes of cones were observed in the perimacular area. Both red/green and blue opsins were distributed along the entire cellular expanse of the cone photoreceptors in the affected eye, but were restricted to the cone outer segments in the control retina. Cone synapses were not observed.
Conclusions: :
The histological data obtained from an elderly male patient with Goldmann-Favre syndrome showed an absence of rods and abnormal distribution of red/green and blue cone opsins.
Keywords: photoreceptors • opsins • retina