Gene mutation spectrum analysis of retinitis pigmentosa patients in Ningxia Region of China

Objective

To analysis the gene mutation spectrum of retinitis pigmentosa (RP) patients in Ningxia Region of China.

Methods

Fifty-five pedigrees and 74 sporadic RP patients were included in Ningxia Eye Hospital from January 2015 to December 2016.Two hundred unrelated healthy adults were enrolled as normal controls during the same period.The clinical features of patients and their family members were evaluated by ophthalmic examinations, including visual acuity, best corrected visual acuity, fundus examination, optical coherence tomography, fundus fluorescein angiography, and visual field and electroretinogram.The next generation sequencing, PCR and direct sequencing were used to confirm the pathogenic mutation.This study was approved by Ethic Committee of the Ningxia Eye Hospital (NO.20150107), and informed consent was obtained from each subject.

Results

The mutations were detected in 37 RP pedigrees, 8 pedigrees showed autosomal dominant inheritance and 6 pathogenic genes were confirmed, all the autosomal dominant RP (ADRP) patients carried a single heterozygous mutation.Twenty-five pedigrees were autosomal recessive RP (ARRP) and 12 pathogenic genes were confirmed.Among ARRP patients, the mutations rate of USH2A gene was the highest, accounting for 28% (7/25), EYS gene and MYO7A gene accounted for 12% (3/25). Four X-linked RP (XLRP) pedigrees carried the homozygous mutations on RPGR gene.Twenty-five disease-causing genes were detected in 49 sporadic RP patients.The mutation rate of USH2A gene was the highest, accounting for 26.5% (13/49), followed by RP1 gene, accounting for 8.1% (4/49).

Conclusions

Recessive inheritance is the most common cause of RP.USH2A gene is the main pathogenic gene of RP in Ningxia region of China.