Novel ocular observations in a child with Joubert syndrome type 6 due to pathogenic variant in TMEM67 gene

To describe unique ocular features in a child with Joubert syndrome type 6. A 4-year-old male patient presented with right microphthalmia and non-dilating pupil and left primary position nystagmus. Brain MRI revealed a “molar tooth sign” of the midbrain and a “batwing sign” of the fourth ventricle along with large retroorbital cysts bilaterally. The diagnosis of autosomal recessive Joubert syndrome type 6 due to homozygous pathogenic variant c.725A > G p. (Asn242Ser) in TMEM67 gene was confirmed by whole exome sequencing. Left eye had nystagmus and the left optic nerve and retina showed epipapillary and subretinal fibrosis, respectively. Scleral buckle was performed for left non-rhegmatogenous retinal detachment which then improved and has been stable. We present a rare case of JS with some unique ophthalmic features which expand clinical knowledge on this complex systemic and ocular entity. •Joubert syndrome is a ciliopathy diagnosed via genetic testing or pathognomonic brain MRI findings.•It can present numerous ocular features including oculomotor apraxia and retinal pathology mostly pigmentary retinopathy.•Epipapillary and subretinal fibrosis can be present in Joubert syndrome. After conducting a literature review on March 20, 2024 utilizing PubMed, Google Scholar and Web of Science search engines using the key words Joubert syndrome (review), eye, retina, optic nerve, fibrosis, we did not find any prior reports of epipapillary and/or subretinal fibrosis reported in any type of Joubert syndrome spectrum.