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The following is a summary of “Bietti’s crystalline dystrophy: genotyping and deep qualitative and quantitative phenotyping in preparation for clinical trials,” published in the July 2024 issue of Ophthalmology by Li et al.
Researchers conducted a retrospective study analyzing the genetic and phenotypic characteristics of Bietti’s crystalline (BCD) dystrophy in a patient cohort.
They enrolled patients with clinically confirmed BCD for genotyping and phenotyping. Various retinal imaging techniques were utilized. The primary criterion for staging was foveal atrophy, while the quantitative measure was the percentage area of autofluorescence (AF) atrophy (PAFA) in the macula.
The result showed 74 patients with clinically diagnosed BCD, the c.802–8_810del17insGC variant of the CYP4V2 gene was identified as the most common, with an allele frequency of 55.4%. A total of 62 patients (123 eyes) with complete imaging data were staged using a modified criterion in stage 1 (n=8, 6.50%), stage 2A (n=9, 7.32%), stage 2B (n=17, 13.82%), stage 3A (n=30, 24.39%), and stage 3B (n=59, 47.97%). Stage 2B eyes were considered high risk due to atrophy near the fovea, while stage 3A eyes, despite significant foveal atrophy, retained retinal pigment epithelium/photoreceptor islands near the fovea in 14 eyes. An age-related increase in the PAFA was observed (rs=0.31, P=0.014). The PAFA significantly increased from stage 1 to stage 3B, and best-corrected visual acuity (BCVA, Logarithm of the Minimum Angle of Resolution) showed a moderate correlation with PAFA (rs=0.56, P<0.001).
Investigators concluded that PAFA was an effective biomarker for BCD severity and that foveal involvement should be prioritized for therapeutic interventions.
Source: bjo.bmj.com/content/108/8/1145
