Abstract
Purpose :
To report variable progression of retinal findings and cataract in two siblings with AHI1-gene associated Joubert syndrome 3. Long-term follow-up is limited in this rare disorder.
Methods :
Two sisters from one family with homozygous AHI1-gene mutations (p.(Thr304Asnfs*6)) were examined and followed for a period over 16 years (18/20-34/36 years of age). Both underwent repeated clinical examinations with testing of visual acuity, visual fields, funduscopy as well as retinal imaging including optical coherence tomopgraphy (OCT), fundus autofluorescence (FAF) and near-infrared autofluorescence (NIA).
Results :
Two sister were first seen at age 18 and 20. Retinitis pigmentosa had been diagnosed in the first and third years of live, respectively. Moderate facial abnormalities were observed and cognitive developmental delays were notable. The younger sister had moderate hearing loss. She had a more severe nystagmus compared to her sister. Both had reduced visual acuity (about 20/100 to 20/50) initially. Visual fields were constricted to 15-20 degrees. OCT, FAF and NIA showed characteristc findings for retinitis pigmentosa in both sisters. In the OCT photoreceptor loss was more marked in the younger sister, who also presented moderate macular edema. During follow-up limited progression of visual field defects were noted in the older sister, the visual acuity remained unchanged. The younger sister developed posterior pole cataract as well as a marked progression of paracentral loss of photoreceptors in the OCT with corresponding findings in FAF/NIA.
Conclusions :
AHI1-gene associated Joubert syndrome 3 is a rare retinal disorder that can present with variable severity of clinical signs and variable progression of retinitis pigmentosa and cataract within one family.
This is a 2020 ARVO Annual Meeting abstract.