Pathogenic variants in WDR45 are associated with iron deposits in the basal ganglia. We aimed to determine iron levels in tears of patients with WDR45 X-linked optic atrophy compared to healthy controls. The study group included two brothers aged 26 and 32 years and a 3-year-old girl from another family diagnosed with optic atrophy, all of whom harbored a novel pathogenic variant in WDR45. Tear samples were collected from the inferior fornix using Schirmer filter strips and analyzed for trace elements using a particle-induced X-ray emission (PIXE) technique and a Fast X123 SDD70 (C2) detector. Concentrations were calculated as the difference from unused Schirmer strips. Findings were compared with 28 healthy subjects, 21 females and 7 males, aged 18–50 years (mean 28.5 ± 9.09 years). All three patients with WDR45 X-linked optic atrophy exhibited elevated iron levels in their tears compared to healthy controls. No differences from the control group were detected for other trace elements. This is the first study to show higher-than-normal iron levels in the tears of patients with X-linked optic atrophy due to a variant in WDR45. The findings broaden our understanding of the role of the WDR45 gene in disorders related to abnormal iron pathophysiology. PIXE analysis is a highly sensitive technique for measuring trace elements in tears. Further clinical studies are needed to investigate potentially novel genotype-phenotype correlations. The application of these findings in clinical practice may benefit patient care.
Michelson et al. (Mon,) studied this question.