ABSTRACT
@#AIM: To analyze the gene mutation spectrum of autosomal recessive retinitis pigmentosa(ARRP)pedigrees and cone-rod dystrophy(CORD)pedigrees in Ningxia region of China. <p>METHODS:Totally 35 ARRP pedigrees and 18 CORD pedigrees were included in Ningxia Eye Hospital from September 2016 to February 2020. Peripheral venous blood samples of the proband were collected for targeted capture enrichment and high-throughput sequencing using a genetic retinal disease capture chip that contain 232 pathogenic genes. Online analysis software was used to predict the pathogenicity of suspicious gene variation, and Sanger sequencing was used to analyze the co-segregation of the family members. <p>RESULTS: Totally 16 pathogenic genes were confirmed in 35 ARRP pedigrees, the mutations rate of RP1 gene was the highest, accounting for 14%(5/35), following were ABCA4, CRB1 and EYS gene, accounted for 11%(4/35); 18 CORD pedigrees carried 10 pathogenic genes. The mutation rate of ABCA4 gene was the highest, accounting for 28%(5/18), followed by ALMS1, PROM1, RPE65, USH2A gene, accounting for 11%(2/18). There were 5 co-exist disease-causing genes in ARRP and CORD pedigrees, which were ABCA4, CLN3, CRB1, PROM1, NRL, accounting for 42%(22/53).<p>CONCLUSION: There are similarities and crossover in the phenotype of ARRP and CORD. The pathogenic genes were overlaped. The most common overlaping gene between the two diseases is ABCA4.
ABSTRACT
Background Retinitis pigmentosa (RP)is a common hereditary blinding eye disease in ophthalmology.Current researches documented that RP may have the common pathophysiologic basis to Alzheimer disease and chronic neurodegenerative disease.Understanding this mechanism will offer a new therapeutic target for RP.Objective The purpose of the present study was to investigate the roles of cyclin-dependent kinase 5 (Cdk5)/P25 activation in the apoptosis of retinal neural cells of RCS rats.Methods Eighteen SPF RCS rats and 18 RCS-rdy+ rats were randomized into 17-,25-and 35-day groups respectively and 6 rats for each.The rats were sacrificed at corresponding time points and retinal hemogenete was prepared.Expressions of CdkS,P35,P25 and tau phosphorylation in the retinas were detected by Western blot,and the kinase activity of Cdk5/P25 was analyzed by quantitative colorimetric assay.Results The expressing level of P35 protein(A340) in the retinas of 17-day-old RCS rats was near that of 17-day-old RCS-rdy+ rats(t =0.52,P＞0.05).In 25-and 35-day-old RCS rats,the expressing levels of P35 protein were 2.20±0.48 and 1.23±0.14,which were higher than those of RCS-rdy+ rats(1.43±0.13 and 0.93±0.10),showing significant differences between them(t =3.78,4.28,P＜0.05).The expression of P25 was undetectable at postnatal 17 days in RCS rats and RCS-rdy+ rats,but it showed significantly higher in RCS rats(0.300±0.003 and 0.230±0.004) than that in RCS-rdy+ rats(0.040±0.004 and 0.070±0.004) at postnatal 25 days and 35 days(t=121.81,77.51,P＜0.01).No significant difference was found in the expression of Cdk5 in RCS rats and RCS-rdy+ rats at different ages (t =-0.60,0.19,1.62,P＞ 0.05).The kinase activity of Cdk5/P25 did not show significantly different between RCS and RCS-rdy+ rats at postnatal 17 days(t =0.19,P＞0.05),but significantly higher kinase activity of Cdk5/P25 was seen in RCS rats (0.0058 ±0.0005 and 0.0056±0.0004) than that in RCS-rdy+ rats(0.0038±0.0003 and 0.0032 ±0.0007) at postnatal 25 days and 35 days (t =8.07,5.97,P＜ 0.01).No expression of tau phosphorylation was detected in RCS rats at postnatal 17 days,but significantly higher tau phosphorylation level was seen in RCS rats at postnatal 25 days and 35 days(1.80±0.22 and 1.23±0.17),which were significant different in comparison with RCS-rdy+ rats at postnatal 25 days and 35 days(1.60 ±0.20 and 1.04 ±0.12)(t=4.71,3.17,P＜0.05).Conclusions The Cdk5/P25 kinase activity shows a consistent trend with theexpressions of P25 and tau phosphorylation in the RCS rats,indicating that the upregulation of P25 induces the enhance of enzyme activity of Cdk5,which phosphorylate its substrates to result in more apoptosis of retinal neural cells.