Relationship between genotype and phenotype in Alport syndrome: analysis at ?5 (Ⅳ) chain mRNA level / 中华肾脏病杂志

ABSTRACT

Objective To analyze type IV collagen a5 chain mRNA and to study the relationship between genotype and phenotype in X-linked Alport syndrome. Methods Total RNA was isolated from the cultured skin fibroblasts of 21 unrelated Chinese X-linked Alport syndrome patients (17 males and 4 females),then ?5 chain (Ⅳ) mRNA was analyzed by using reverse-transcription-polymerase reaction (RT-PCR) and direct sequencing. Meanwhile,by using PCR and direct sequencing,detection of COL4A5 gene mutations at genomic DNA level was carried out. Results Abnormal ?5 chain IV cDNA was detected in 21 X-linked Alport syndrome patients,and seventeen mutations detected in this study were novel mutations. In 15/21 of patients,identical COL4A5 mutations were detected both at mRNA level and genomic DNA level,and in 6/21 of patients with splicing-site mutations,changes in transcript structure differed from changes in genomic DNA level. 16/21 of patients belonged to X-linked juvenile kindreds,and 2/21 of patients to adult kindreds. Conclusion Different type of mutations in COL4A5 can lead to the severe form of X-linked Alport syndrome,and mRNA-based procedures can both directly detect mutations in the coding sequences,as well as changes in transcript level or structure,and can identify some abnormalities that would otherwise have been missed by DNA-based procedures.