Abstract
Purpose: :
To describe the phenotype variation in a Swedish family with enhanced S cone syndrome (ESCS).
Methods: :
The male proband, his and five siblings and their mother were investigated with full-field ERG, multifocal ERG (mfERG), optical coherence tomography (OCT) and fundus autofluorescence photography (FAF). Molecular genetic analysis of NR2E3 was performed.
Results: :
The male proband age 24 was diagnosed with ESCS ten years ago. The heterozygous mutation p.E121K was identified in NR2E3 in the proband. This mutation has been associated with ECSC previously. The proband harboured atypical nummular deep pigmentation throughout the peripheral fundi. Full-field ERG demonstrated reduced rod, rod-cone and 30 Hz flicker cone responses (<50% of lower range of normal for all), and there was no demonstrable progression during 10 years of follow-up. MfERG demonstrated preserved central function and peripheral reduction. OCT demonstrated epiretinal fibrosis and microcystic changes in the inner retinal layers. Visual fields were normal by Goldmann object V:4, however for object I:4 there was a progression from 70 degrees temporally to 30 degrees during 10 year follow-up.The mother had widespread confluent peripheral atrophic areas reminiscent of gyrate atrophy, and barely measurable rod and cone function by full-field ERG already at presentation at age 40 years. Visual fields by Goldmann object I:4 were reduced to <10 degrees temporally.All siblings had normal visual fields and full-field ERGs.
Conclusions: :
The phenotypes varied widely within this family with ESCS. Visual fields were progressively constricted for objects I:4 in affected individuals. In addition, central retinal structural alterations were demonstrated, with relative preservation of function.
Keywords: retinal degenerations: hereditary • photoreceptors • genetics