Rare West African crystalline maculopathy characterized by appearance and genetics

A case series of West African crystalline maculopathy (WACM) was analyzed to better understand the condition’s etiology, clinical and genetic features, and potential preventive and intervention strategies. Through OCT, WACM’s characteristic macular hyperrefractile crystal-like deposits were readily detected.

Study design

This prospective, cross-sectional cohort study identified patients with WACM from the larger pool of patients who enrolled in the Ghana AMD (GAMD) Study. The GAMD Study was designed to analyze the clinical and genetic features of AMD in the Ghanaian population.

Outcomes

Of the full dataset of 1056 participants in the GAMD study, 106 eyes of 53 participants were diagnosed with WACM by 3 retina specialists. Mean age was 68.4 years for the WACM patients. In typical WACM, the crystals were predominantly located at the internal limiting membrane and the Henle fiber layer, as shown by color fundus photograph and/or OCT. With high-contrast OCT, the crystals were highly visible and bright while other hyperreflective lesions appeared less obvious. In eyes with other macular pathology, as with neovascular AMD, crystals were observed deeper in the inner retina, though WACM crystals were also found throughout the retinal layers. Age, sex, and kola nut consumption were not correlated with WACM; however, the complement factor H 402H variant showed significant association.

Limitations

Although this study is the largest cohort of WACM found in the literature, the condition is diagnosed on a relatively rare basis.

Clinical significance

Although a rare condition, this is an important diagnosis to consider in patients of West African origin, especially given this study's findings of its association with macular degeneration and shared genetics.