Novel mutation c.1210-3C & gt; G in cis with a poly-T tract of 5T affects CFTR mRNA splicing in a Chinese patient with cystic fibrosis

AbstractCystic fibrosis (CF) is a rare autosomal recessive disease with only one pathogenic gene cystic fibrosis transmembrane conductance regulator (CFTR). To identify the potential pathogenic mutations in a Chinese patient with CF, we conducted Sanger sequencing on the genomic DNA of the patient and his parents and detected all 27 coding exons ofCFTR and their flanking intronic regions. The patient is a compound heterozygote of c.2909G> A, p.Gly970Asp in exon 18 and c.1210-3C> G incis with a poly-T of 5T (T5) sequence, 3 bp upstream in intron 9. The splicing effect of c.1210-3C> G was verified via minigene assayin vitro, indicating that wild-type plasmid containing c.1210-3C together with T7 sequence produced a normal transcript and partial exon 10-skipping-transcript, whereas mutant plasmid containing c.1210-3G incis with T5 sequence caused almost all mRNA to skip exon 10. Overall, c.1210-3C> G, the newly identified pathogenic mutation in our patient, in combination with T5 sequence incis, affects theCFTR gene splicing and produces nearly no normal transcriptin vitro. Moreover, this patient carries a p.Gly970Asp mutation, thus confirming the high-frequency of this mutation in Chinese patients with CF.
Source: Frontiers of Medicine - Category: General Medicine Source Type: research