Enhanced S-cone syndrome: Clinical spectrum in Indian population

Abstract

Purpose: Enhanced S-cone syndrome (ESCS), a rare disorder, is often misdiagnosed as other forms of retinal degenerations, which have a poorer prognosis than ESCS. The aim of this study is to report the varied clinical features of ESCS and distinguish it from other similar disorders. Methods: We retrospectively scrutinized the records of patients with confirmed diagnosis of ESCS and analyzed the findings. Results: We included 14 patients (age range 4–39 years) who were confirmed to have ESCS according to pathognomonic electroretinography (ERG) showing reduced photopic, combined responses, and 30 Hz flicker with reduced L, M cone responses and supernormal S cone responses. The disease presented in the 1 st decade with night blindness and was almost stationary or minimally progressive. Mid-peripheral fundus changes in form of nummular pigmentary alterations, yellow punctate lesions, and macular schisis were noted. The vision ranged from 6/6 to 6/36 with follow-up ranging from 1month to 22 years. Conclusion: ESCS shows varied clinical features ranging from unremarkable fundus to pigment clumping and atrophic lesions. It has good prognosis with patients mostly maintaining their vision. ERG is diagnostic. More awareness and knowledge about this entity can help to differentiate it from other forms of night blindness.

Suspected Enhanced S-Cone Syndrome: A Case Report

“…However, the typical appearance is nummular pigmented deposits at the level of retinal pigment epithelium and intraretinal cysts. Yellow pigmentation in the mid-peripheral fundus was reported by Naik et al as the most common fundus finding [ 1 ].…”

“…The usual age of presentation has been reported to be the first two decades of life [ 2 ]. Despite Naik et al reported that only five patients in their series presented in their first decade, previous misdiagnoses of other patients as having other types of retinal dystrophies probably caused the delay in presentation [ 1 ].…”

“…In this disorder, the short-wavelength-sensitive cone photoreceptors are hypersensitive. On the other hand, rods, M-, and L-cone receptors are degenerated [ 1 ].…”

“…ESCS may be misdiagnosed as other retinal dystrophies, such as retinitis pigmentosa and congenital stationary night blindness. Fundus examination in ESCS shows characteristic nummular pigmentary changes at the level of the retinal pigment epithelium along the vascular arcades, and sometimes in the posterior pole, and these can then progress to the more classic pigmented lesions [ 1 ]. Other reported findings include cystoid maculopathy, foveal, and peripheral schisis.…”

Bilateral Helicoid Peri-papillary Sub-retinal Fibrosis Due to a Biallelic NR2E3 Mutation: Describing Variable Expressivity of a Single Genetic Mutation

“…These include autosomal recessive Goldmann-Favre syndrome, autosomal recessive or dominant enhanced S-cone syndrome (ESCS), autosomal recessive clumped pigmentary retinal degeneration, autosomal recessive or dominant retinitis pigmentosa, and "torpedo-like" lesions in posterior pole or along the vascular arcades. [2][3][4][5][6][7][8][9][10][11] This mutation has been reported to cause both dominant and recessive form of retinal dystrophy in the same family. These variable presentations of a single genetic mutation make a challenge for establishing the correct diagnosis based on clinical ndings.…”