Authors: Han Xiaoxu, Li Hui, Wu Shijing, Sun Zixi, Zhou Qi, Sui Ruifang
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Objective
To provide detailed clinical and molecular genetic findings and describe the characteristics of natural history in Chinese choroideremia (CHM) patients.
Methods
The patients with CHM who met the inclusion criteria of at least two visits over a minimum period of 5 years were recruited on a voluntary basis at the Ophthalmic Genetics Clinic in Peking Union Medical College Hospital from April 2009 to August 2017.Molecular genetic analysis results, best-corrected visual acuity (BCVA), color fundus photograph, optical coherence tomography (OCT), visual field (VF), full-field electroretinography (fERG) were obtained.This study protocol was approved by the Institutional Review Board of Peking Union Medical College Hospital (S-K125). Written informed consent was obtained from each participant.
Results
Ten Chinese Han patients from seven CHM families were included.The mutations were confirmed by molecular genetic analysis, and two novel mutations were found.The median age of 10 patients at first visit was 44 years (range 8-52 years). The mean first-last visit period was 6.08 years (range 5.03-7.24 years). The mean BCVA at first visit in logMAR equivalents was 0.56 (range 0.0-2.0) or approximately 0.28 decimal acuity.The correlation between BCVA at first visit and age showed that relative good vision remained until 35 years old and BCVA subsequently reduced rapidly.OCT showed a thickening of the central retinal thickness at early stage, followed by a thinning over decades.Outer retinal tabulation (ORT) was shown in some patients.There was a strong negative correlation (r=-0.861, P<0.001) between residual VF and age.Five patients did not need to record fERG because of serious fundus lesions.Two patients exhibited decreased amplitudes for both rod and cone-driven responses, and three patients exhibited no fERG amplitudes.
Conclusions
The progression of CHM may be severer and faster in Chinese patients than that in Western patients.ORT is an important manifestation of OCT in CHM patients.VF and fERG are applicable to evaluate the condition of very-early phase of CHM.