Abstract:
Objective To study the phenotypic characteristics and genetic classification of nonsyndromic retinitis pigmentosa in a Chinese family, and screen the disease-causing gene mutations.
Methods The family in the study came from Shandong Province, which included 3 generations with 21 members (4 patients, 17 healthy individuals). The peripheral venous blood of 8 individuals(4 patients, 4 healthy individuals) in the family were collected. Ophthalmological examinations including uncorrected visual acuity, best corrected visual acuity, biomicroscopy of the anterior eye segment, applanation tonometry, fundus examination, spectral-domain optical coherence tomography (SD-OCT), and electroretinogram (ERG) were performed to the eight members. A pedigree figure was drawn after the history taking. Then, DNA isolation and sequencing were performed to determine the inheritance pattern and screen the suspected mutations.
Results Night blindness, decreased visual acuity and visual field constriction were observed in four patients, and fundus photography showed a waxy yellow optic nerve head,attenuation of vessels, bone spicule deposits in the retina. The four patients in the family were all diagnosed as nonsyndromic retinitis pigmentosa, and symptom emerged earlier in Ⅲ 2 and Ⅲ 5 of the third generation thanⅡ 7 andⅡ9 of the second generation.
Conclusion The USH2A gene is the disease-causing gene of the family, and its inheritance pattern is autosomal recessive. Compound heterozygous mutations in USH2A (c.4649C> A and c.970G> A) may cause the pathological changes.