mRNA analysis of the cystic fibrosis transmembrane regulator (CFTR) gene in tissues of cystic fibrosis (CF) patients has allowed us to detect a cryptic exon. The new exon involves 49 base pairs between exons 11 and 12 and is due to a point mutation (1811 + 1.6kbA→G) that creates a new donor splice site in intron 11. Semiquantitative mRNA analysis showed that 1811 + 1.6kbA→G-mRNA was 5-10-fold less abundant than ΔF508 mRNA. Mutation 1811 + 1.6kbA→G was found in 21 Spanish and 1 German CF chromosomes, making it the fourth-most-frequent mutation (2%) in the Spanish population. Individuals with genotype ΔF508/1811 + 1.6kbA→G have only 1%-3% of normal CFTR mRNA. This loss of 97% of normal CFTR mRNA must be responsible for the pancreatic insufficiency and for the severe CF phenotype in these patients.
|Number of pages||7|
|Journal||American Journal of Human Genetics|
|Publication status||Published - 1995|
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