X-linked juvenile retinoschisis (XLRS) has been well-documented in Finnish and other white populations. This case report illustrates a well-recognised condition in a rare population group. There are few case reports in literature of XLRS in black populations.
X-linked juvenile retinoschisis (XLRS) is an X-linked recessive bilateral retinal dystrophy that affects young males in their first decade of life.
Patients typically present with poor vision or difficulty in reading in the first decade of life.
Clinically symmetrical foveal schisis (splitting of the retina)
Optical coherence tomography (OCT) has become an important diagnostic examination
The differential diagnosis for bilateral foveal schisis includes conditions that cause cystic macular changes, with the emphasis on those that do not cause leakage on fundus fluorescein angiography (FFA). These include inherited conditions such as X-linked congenital stationary night blindness (XLCSNB) and Goldmann–Favre vitreoretinal degeneration (GFVD).
A recently described foveomacular retinoschisis called stellate non-hereditary idiopathic foveomacular retinoschisis can have a clinical presentation almost identical to XLRS, but this has been described in females and has unilateral involvement, and genetic testing is negative for the RS1 gene.
In terms of management, this is focused on potential complications.
Mr T.M. is a 23-year-old black South African male with a history of mild myopia, who presented at age 19 with the main complaint of bilateral gradual loss of vision. He did not have a notable history of nyctalopia nor a history of trauma or chronic medication use. He had no significant family history of a loss of vision. He has a 2-year-old daughter, who has no ocular complaints. There is also no known mixed-ancestry in his family. He works as a supervisor at a merchandising company and is a non-smoker and social drinker. On examination, his best-corrected Snellen visual acuity was 6/12 bilaterally, with a subjective refraction of: Plano/−1.75 axis 90° for the right eye and −0.25/−1.75 axis 84° for the left eye. On slit-lamp biomicroscopy, his anterior segment examination was normal; his intraocular pressures were 12 mm Hg and 13 mm Hg for the right and left eye respectively. His lenses were clear bilaterally. He had bilateral syneretic vitreous and on fundoscopy he exhibited a bilateral, symmetrical spoke-like pattern at the macula. His optic nerves were normal with a cup-to-disc ratio of 0.3 and no optic nerve pit was noted. No peripheral retinal abnormalities were seen; there were no features of a myopic fundus and no pigmentary changes were noted. No peripheral retinoschisis was evident.
Spectral domain-optical coherence tomography (SD-OCT) confirmed a bilateral, symmetrical foveal schisis (see
Spectral domain-optical coherence tomography of the right (a) and left eye (b) respectively. There are splitting/cystic changes in the inner nuclear layer (INL), the outer plexiform layer (OPL) and the outer nuclear layer (ONL). A finding consistent with XLRS cases in current literature (Schofield et al. 2016)
(a, b) Fundus autofluorescence (FAF) and (c, d) fundus fluorescein angiography (FFA) images of the right and left eye respectively. In the fundus autofluorescence images the ‘spoke-like’ pattern is clearly highlighted. The fundus fluorescein angiography shows no active leakage, with mild pooling at the macula.
Electrophysiological tests revealed a diminished b-wave (
Electroretinogram (ERG) showing a selective reduction in b-wave amplitude.
Ethical clearance to conduct this study was obtained from the Human Research Ethics Committee (medical), University of the Witwatersrand, Johannesburg (ethical clearance number: M190699).
When considering the rare diagnosis of XLRS in this case, as mentioned previously, there are certain differentials one needs to exclude in a patient presenting with bilateral, symmetrical foveal schisis. Macular schisis associated with myopia is a more common, similar presentation. It is thought that after a posterior vitreous detachment, residual cortex can cause tangential traction on the macula, and in association with anterior–posterior forces of a staphyloma, macular schisis occurs.
X-linked juvenile retinoschisis (XLRS) is well-documented in the literature. The highest prevalence is in Finland.
Hypermetropia is usually an association, although this association was not found in our patient or the Nigerian case report.
The authors would like to thank Dr Tebogo Maleka for his assistance with the imaging of the patient. They also thank the Steve Biko Academic Hospital Neurophysiology Laboratory for performing the electroretinogram on the patient.
The authors have declared that no competing interests exist.
Both authors contributed equally to this work.
This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.
Data sharing is not applicable to this article as no new data were created or analysed in this study.
The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of any affiliated agency of the authors.