Objectives To study the relationships between methylenetetrahydrofolate reductase(MTHFR ) gene polymorphism and diabetic retinopathy (DR) in Chinese Han race． Methods With polymerase chain reaction and restriction fragment length polymorphism (PCR-FLP), MTHFR gene 677 T mutation (cytosine is replaced by thymine in No. 677 site) was detected in 85 health controls, 62 with DR and 117 without DR of type 2 diabetics comfrimed by ophthalmoscope． Results The frequency of MTHFR variant genotypes and alleles of DR in Chinese Han race．patients were signigicantly higher than those without retinopathy and healthy controls (Plt;0．01)． Conclusions The results suggested that MTHFRgene C677T mutation was probably one of the genetic risk factors of diabetic retinopathy in Chinese Han rase． (Chin J Ocul Fundus Dis, 2001,17:198-200
Objective To investigate whether mutations exist in codon 58 and codon 347 of the rhodopsin gene in patients with autosomal dominant retinitis pigmentosa(ADRP)． Methods Point mutations at codons 58 and 347 were detected by restriction endonuclease digestion of exons 1 and 5 amplified by polymerase chain reaction(PCR)．This method was applied to screen genomic DNAs from 57 patients of 38 families with ADRP and 60 normal controls． Results Four patients from one family of ADRP were confirmed to have a point mutation at the second nucleotide of codon 58,and 6 patients from two families of ADRP were found to have a mutation at codon 347．None of these mutations were found in 60 normal subjects． Conclusion It is suggested that molecular genetic heterogeneity exists within ADRP and some subtypes of ADRP are caused by points mutations of the rhodopsin gene． (Chin J Ocul Fundus Dis,1998,14:108-110)