Posterior Polar Annular Choroidal Dystrophy: Genetic Insights and Differential Diagnosis in Inherited Retinal Diseases

Abstract

Posterior polar annular choroidal dystrophy (PPACD) is a rare ocular disorder and presents as symmetric degeneration of the retinal pigment epithelium (RPE) and the underlying choriocapillaris, encircling the retinal vascular arcades and optic disc. This condition distinctively preserves the foveal region, optic disc, and the outermost regions of the retina. Despite its distinct clinical presentation, due to the infrequency of its occurrence and the limited number of reported cases, the pathophysiology, and the genetic foundations of PPACD are still largely uncharted. This review aims to bridge this knowledge gap by investigating potential genetic contributors to PPACD, assessing current findings, and identifying genes that warrant further study. Emphasis is also placed on the crucial role of multimodal imaging in diagnosing PPACD, highlighting its importance in understanding disease pathophysiology. By analyzing existing case reports and drawing comparisons with similar retinal disorders, this paper endeavors to delineate the possible genetic correlations in PPACD, providing a foundation for future genetic research and the development of targeted diagnostic strategies.

Keywords: central areolar choroidal dystrophy; choroideremia; gyrate atrophy of retina and choroid; inherited retinal diseases; multimodal imaging; posterior polar annular choroidal dystrophy; retinal pigment epithelium; retinitis pigmentosa; spectral domain optic coherence tomography.

Figure 1

Schematic view of the choroid. Arrows show the choroidal vessel layers; choriocapillaris (CC), Sattler’s layer (SL) and Haller’s layer (HL) (graphics courtesy of Dariush Rahimi).