Choroidal and Retinal Imaging Findings in Childhood-Onset Mevalonate Kinase Deficiency: An OCT-Based Case–Control Study

Aim To compare macular microvascular and microstructural exploratory imaging findings in patients with childhood-onset mevalonate kinase deficiency (MKD) and healthy controls, and to assess associations with disease activity.Methods This cross-sectional case–control study included patients with childhood-onset, genetically confirmed MKD and healthy controls. Disease activity was assessed using the autoinflammatory disease activity index (AIDAI) score and C-reactive protein (CRP) levels. Choroidal images were obtained to measure subfoveal choroidal thickness (SFCT) and to calculate the total choroidal area (TCA), luminal area (LA), stromal area (SA), and the choroidal vascularity index (CVI). Macular optical coherence tomography (OCT) and optical coherence tomography-angiography (OCT-A) parameters were compared between groups, and associations with systemic disease activity were examined.Results The study included 17 patients with childhood-onset MKD and 30 healthy controls. The MKD group showed higher LA and CVI than in controls (p = 0.042 and p = 0.014, respectively), whereas TCA and SA were comparable between groups (p = 0.124 and p = 0.669, respectively). Mean central macular thickness was lower in the MKD group (p = 0.030), while SFCT was comparable between groups (p = 0.325). No significant differences were observed in macular microvascular parameters.Conclusion Patients with childhood-onset MKD showed higher CVI, whereas macular microvascular parameters were comparable to those of controls. These findings may suggest subtle alterations in choroidal vascular composition, potentially related to the underlying inflammatory milieu; however, given that all patients were receiving canakinumab treatment, they should be interpreted cautiously as exploratory associations requiring confirmation in longitudinal studies.