Retinal pathology occurs in stiff-person syndrome

Abstract

Objective: To evaluate whether structural and functional changes occur in the afferent visual system of patients with stiff-person syndrome (SPS) and whether these changes correlate with disease burden, given the high concentration of γ-aminobutyric acid receptors, which are generally thought to be involved in SPS pathogenesis, in the retina.

Methods: In this single-center, cross-sectional study, patients with SPS and healthy controls (HCs) underwent optical coherence tomography (OCT), with a subset undergoing high- and low-contrast visual acuity (VA) assessments. Burden of disease was assessed via the number of body regions affected. Individuals with uncontrolled hypertension or comorbid neurologic or ophthalmologic disorders were excluded. Statistical analyses were performed using mixed-effects linear regression models.

Results: Thirty-five patients with SPS and 40 age- and sex-matched HCs underwent OCT. A subset of 23 patients with SPS and 28 HCs underwent VA assessments. Relative to HCs, patients with SPS had lower ganglion cell + inner plexiform layer (GCIPL) thicknesses (SPS: 74.36 µm [SD 5.7]; HCs: 76.33 µm [SD 4.2]; p = 0.005), inner nuclear layer thicknesses (SPS: 44.37 µm [SD 2.7]; HCs: 45.18 µm [SD 2.2]; p = 0.042), and 100% (SPS: 53 [SD 9.6]; HCs: 57.5 [SD 6.1]; p = 0.005), 2.5% (SPS: 24.35 [SD 10.1]; HCs: 30.16 [SD 7.7]; p = 0.006), and 1.25% contrast (SPS: 16.41 [SD 10.6]; HCs: 20.84 [SD 8.6]; p = 0.034) letter acuity scores. GCIPL thicknesses correlated with the number of body regions affected in SPS (decrease of 1.25 µm [95% confidence interval, -2.2 to -0.3 µm; p = 0.008] per additional body region affected).

Conclusions: Retinal neuronal pathology can occur in SPS. OCT may have utility as a biomarker of disease burden in SPS.