Temporal retinal thinning might be an early diagnostic indicator in male pediatric X-linked Alport syndrome

Abstract

AIM: To evaluate temporal retinal thinning changes in retinal layers using spectral-domain optical coherence tomography (SD-OCT) in pediatric X-linked Alport syndrome (XLAS) patients. METHODS: A retrospective case-control study. SD-OCT scans of pediatric patients diagnosed with XLAS and age- and sex-matched healthy control participants were reviewed. Automated segmentation of SD-OCT scans was induced to analyze the retinal thickness (RT) of different layers. The temporal thinning index (TTI) was calculated for each layer and compared between the patients and the control group. RESULTS: Forty-three pediatric XLAS patients and 60 healthy controls were included. Temporal retinal thinning was present in 33 patients (76.74%), while 28 patients (65.11%) had severe pathological temporal retinal thinning and 5 patients (11.63%) had moderate thinning. The temporal inner sector RT (P<0.0001), the temporal outer sector RT (P<0.0001), and the nasal outer sector RT (P=0.0211) were significantly thinner in the XLAS male patients. The TTI of the total retina was significantly higher in the XLAS group than in the control group (P<0.0001). The TTI of the inner retina layers (P<0.0001), ganglion cell layer (P<0.0001), inner plexiform layer (P<0.0001), inner nuclear layer (P<0.0001), and outer nuclear layer (P<0.0001) were significantly higher in the XLAS group. The central RT of the XLAS group was significantly thinner than that of the control group (P<0.0001). CONCLUSION: Temporal retinal thinning appears early in XLAS patients, especially in male patients. The thinning is mainly caused by structural abnormalities of the inner retina. This suggests that temporal retinal thinning could be helpful for the early diagnosis and follow-up of XLAS with noninvasive SD-OCT examination.

Characterization of Ocular Morphology in Col4a3−/− Mice as a Murine Model for Alport Syndrome

“…Approximately 20% to 90% of patients with AS have ocular abnormalities. 1 Some characteristic ocular manifestations, such as anterior lenticonus 17 and temporal retinal thinning, 18 have great value for assisting in the diagnosis of AS. Nevertheless, studies on AS-related ocular diseases are still insufficient.…”

“…The incidence of fleck retinopathy in patients with AS is about 50% to 70%, 30 whereas the incidence of temporal retinal thinning may be as high as 90% in patients with AS. 4 , 18 Because mice lack a retinal macular area, we did not study fleck retinopathy in Col4a3 −/− mice. Cho et al 31 examined the retina of patients with AS by stratified Enface optical coherence tomography (OCT) scanning and found retinal flecks in the ILM and RPE basement membrane by horizontal scanning.…”

“…Our previous study revealed that 76.74% of patients with XLAS exhibited temporal retinal thinning. 18 Chen et al 33 reported that 89% of male patients with XLAS, 75% of female patients with XLAS, and 100% of patients with autosomal recessive AS experienced temporal retinal thinning. Researchers have noted that the temporal thinning index (TTI) calculated with retinal thickness is of great value in the diagnosis of AS.…”

“…We previously found that the retinal inner layers were thinning in patients with XLAS, including GCL, IPL, and INL. 18 Furthermore, Savige et al 32 compared retinal thickness in each quadrant of the macular area in patients with AS and found that the decrease in retinal thickness was due to thinning of the inner layers, including ILM/nerve fiber layer (NFL) and INL. In this study, we found that retinal thinning in Col4a3 −/− mice due to the thinning of the IPL, which is in accordance with the results reported in patients.…”