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Progressive retinal layer thinning in MAK-RP highlights the need for alternative markers to monitor preserved central vision over time.  

Researchers conducted a retrospective study published In June 2025 issue of American Journal of Ophthalmology to describe the clinical features and disease progression patterns in individuals with Male Germ Cell-Associated Kinase (MAK)-associated retinitis pigmentosa (MAKRP).  

They reviewed records of 18 individuals (7 female) from 16 families with confirmed pathogenic mutations in the MAK gene and a diagnosis of RP, identified by the Division of Ophthalmic Genetics at Columbia University Irving Medical Center. Each participant underwent a comprehensive retinal evaluation, including fundus autofluorescence (FAF) and spectral-domain optical coherence tomography (SD-OCT). The full field electroretinogram (ffERG) was performed on 12 individuals, and visual field testing was conducted in 5. They measured and compared progression rates of the ellipsoid zone (EZ) and outer nuclear layer (ONL) across both eyes.  

The results showed all individuals were homozygous for MAK-RP (Alu insertion at exon 9), with age at initial assessment ranging from 20 to 83 years. The median BCVA was 20/25 in both eyes. Cystoid macular edema was observed in 33% of cases. The mean EZ horizontal width at baseline measured 3,781 μm and declined at a rate of 209.78 μm/year (95% CI: 181.37–238.18, P< 0.001). Foveal ONL thickness decreased by 1.24 μm/year (95% CI: 0.51–1.97, P= 0.001), adjusted for age and intra-individual variability. The FAF initially showed an irregular hyperautofluorescent ring with more pronounced nasal and inferior photoreceptor loss, progressing to a defined ellipsoid around the macula by the fifth decade. Foveal involvement appeared in some cases by the seventh decade and ffERG revealed attenuated photopic responses in 83% (10/12) and detectable rod responses in 55% (6/11) of participants.  

Investigators concluded that individuals with MAK-associated RP preserved central vision into later life, with significant declines in EZ width and ONL thickness. 

Source: ajo.com/article/S0002-9394(25)00335-6/abstract