Abstract
Purpose :
The pigmented paravenous chorioretinal atrophy (PPRCA) is a rare disease first reported in 1937 as retino-choroiditis radiata and diagnosed by the presence of chorioretinal atrophy and pigment accumulation along the retinal veins. As a cause of PPRCA, crumbs homolog 1 gene mutation has been reported in some families. Because a Caucasian case of PPRCA due to Hexokinase 1 (HK1) mutation was recently reported, we re-examined Japanese cases diagnosed with RP79 due to HK1 mutation.
Methods :
This study was conducted according to the Declaration of Helsinki and approval of the ethical committee (No.719-2) was obtained. We first extracted RP79 patients (HK1: Glu847Lys) from our cohort of hereditary retinal degenerations (IRDs), which analyzed genetically, and then identified two Japanese families. All participants underwent complete ophthalmic examinations, including ultra-widefield retinal imaging (UWFI). For sequencing, Illumina's Hiseq 2500 Platform was used. HK1 mutation (Glu847Lys) was validated by PCR direct sequence with Sanger’s method.
Results :
Case 1: A 60-year-old Japanese woman complained metamorphopsia. Ophthalmic examination revealed best-corrected visual acuity (BCVA) in decimal units was 1.0 in each eye. UWFI revealed symmetrical nasal predominant chorioretinal atrophy surrounding the macula and pigment aggregation consistent with the atrophic lesion. In addition, degeneration was seen along the retinal vessels with starfish-like protrusions. Genetic testing did not detect any mutations other than HK1（Glu847Lys）that are candidates for genes responsible for IRDs.
Case 2: A 75-year-old Japanese man have already reported as RP79 (Ophthalmic genetics, 2019). His BCVA was 1.0 on the right and 0.8 on the left. UWFI revealed symmetrical retinal degeneration with starfish-like projections along retinal vessels avoiding the macula. The characteristics of this case were very similar to those of Case 1.
Conclusions :
In this study, we re-examined two cases of RP79 due to HK1 mutation in our cohort. Detailed examination revealed chorioretinal atrophy and pigment clumping with starfish-like protrusions along the veins in both cases. The phenotype of our Japanese cases was very similar with a Caucasian reported earlier showing macular-sparing degeneration and PPRCA findings. The phenotypic similarities across races may provide insight into the pathogenesis of retinal degeneration caused by HK1 mutations.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.