COMPARATIVE ANALYSIS OF DISEASE-ASSOCIATED MUTATIONS IN THE CODING REGIONS OF ALTERNATIVELY AND CONSTITUTIVELY SPLICED HUMAN GENES

To better understand the evolutionary and molecular mechanisms of alternative splicing causing human diseases, we have systematically compared the pattern, the distribution and the density of disease-associated mutations as well as the influence of codon usage bias on the single mutation between alternatively and constitutively spliced genes through analysis of the large datasets from human disease genes. The results indicated that: 1. The most common pattern of single mutation in alternatively and constitutively spliced genes are, respectively, C/T (25.17%), (22.81%) and G/A (21.54%), (22.73%), suggesting that the two types of disease genes are prone to C → T and G → A mutations. 2. There is an overall preponderance for transitions over transversions in alternatively (62.88% versus 37.12%) and constitutively (64.41% versus 35.59%) spliced disease genes. 3. For the second base of codons, there exist significant differences in transitions and transversions between the two types of genes. 4. Our data indicated that the single mutation tends to occur preferentially when the upstream neighboring-nucleotide is C or G in human disease genes. 5. Codon usage bias and synonymous codon usage have great influence on the single mutation in both alternatively and constitutively spliced genes. The GC content and gene length also have very evident influence on such mutations. Our results seem to imply that disease-associated mutations within the coding regions of alternatively spliced human disease genes have different mechanisms from constitutively spliced genes. Such findings may facilitate understanding the molecular mechanism of alternative splicing causing human diseases, and the development of gene therapies for such diseases.