Inherited retinal degeneration including retinitis pigmentosa with mutations in CRB1, CRX, RPGR, etc. and Leber congenital amaurosis with CEP290 mutation can be rarely accompanied by Coats-like exudative retinopathy [1]. Joubert syndrome, a rare, autosomal recessive disorder characterized by congenital malformations of the brainstem and the cerebellar vermis [2], can present with various ophthalmological abnormalities such as nystagmus, oculomotor apraxia, strabismus, retinal dystrophy, and ocular coloboma [3]. Among the >40 causative genes, CEP290, AHI1, NPHP1, MKS1, and INPP5E-related Joubert syndrome is often accompanied by retinal degeneration [4]. There has been one case report on Coats-like retinopathy in a patient with clinically diagnosed Joubert syndrome without genetic testing [5]. Herein, we report the first case of Coats-like exudative retinopathy in a Joubert syndrome patient with CEP290 mutation. Written informed consent was obtained from the patient’s parent for the disclosure of detailed research information and clinical images.

A 17-month-old Korean female patient, diagnosed with Joubert syndrome, was referred to the ophthalmology clinic for the evaluation of accompanying ophthalmic abnormalities. The patient, born at full term with a birth weight of 3.2 kg, exhibited difficulties in sustaining proper neck alignment and did not engage in suitable eye-to-eye interaction by the age of 100 days. Clinical examination revealed generalized muscle hypotonia. Brain magnetic resonance imaging identified the “molar tooth sign,” and renal ultrasonography showed nephrological abnormalities. These findings confirmed the clinical diagnosis of Joubert syndrome. Ophthalmic examination revealed binocular instability in fixation and tracking, accompanied by nystagmus. By the age of 4 years, fundus examination revealed bilateral retinal degeneration with vascular attenuation (Fig. 1A, 1B). When the patient was 6 years old, the fundus examination showed diffuse whitish-yellowish exudates in the right eye and macular sparing yellowish exudates in the left eye (Fig. 1C, 1D). Fluorescein angiography (FAG) showed bilateral peripheral retinal nonperfusion, telangiectasia, and multifocal fluorescein leakage (Fig. 1E, 1F). However, on follow-up fundus examinations, retinal exudation decreased spontaneously.

Two years later, the patient developed a serous retinal detachment accompanied with telangiectatic vessels in the left eye (Fig. 1G, 1H). Examination under anesthesia with FAG revealed that the right eye showed no fluorescein leakage and exhibited features of diffuse retinal dystrophy associated with Leber congenital amaurosis (Fig. 1I, 1J). In contrast, the left eye showed bullous retinal detachment (Fig. 1K, 1L). Therapeutic intervention for the patient included external subretinal fluid drainage and intravitreal anti-vascular endothelial growth factor (anti-VEGF) injection. One month after treatment, fundus examination and ultrasonography showed a significant reduction in subretinal fluid in the left eye. FAG revealed 360° telangiectatic vessels with peripheral nonperfusion, and profuse fluorescein leakage (Fig. 1M, 1N). Laser photocoagulation was performed at non-perfused area and telangiectatic vessels. One month after the laser photocoagulation, fundus examination showed flat retina with hard exudate, and ultrasonography showed no subretinal fluid (Fig. 1O, 1P).

Whole genome sequencing of the patient and parents revealed compound heterozygous mutations in the CEP290 gene ( NM_025114.4): c.6012-12T>A and c.3175dup (p.Ile1059AsnfsTer11). Thus, the patient was diagnosed as CEP290-related Joubert syndrome.

The patient represents, to the best of the authors’ knowledge, the first case of Coats-like exudative retinopathy in a patient with Joubert syndrome by CEP 290 mutation. Regular fundus examinations for retinal abnormalities in Joubert syndrome may be necessary. When Coats-like retinopathy develops in patients with Joubert syndrome by CEP 290 mutations, laser treatment with or without anti-VEGF treatments can be considered.