Mutation analysis of disease causing proteins

Usually, a disease is caused by different types of mutation in proteins. These mutations could be any of or combination of missense/nonsense, splicing, regulatory, small deletions, small insertions, small indels, gross deletions, gross insertions/duplications, complex rearrangement, repeat variations, etc. In the present study, we explore the mutation pattern of nucleotide and amino acid in disease-causing proteins based on missense and nonsense mutations only. Some diseases are caused due to mislocalization of proteins to a location other than the target and this happens due to changes or mutation in targeting signals. In our study, we divided the disease causing proteins into two groups: Group-1 is composed of proteins that cause disease due to mislocalization and Group-2 is composed of proteins that cause disease without changing their localization. Proteins in Group-1 are called mislocalized proteins and those in Group-2 are called non-mislocalized proteins. Our results show that in both categories (mislocalized and non-mislocalized), 32% to 35% mutations happen to nucleotides C and G and 15% to 18% mutations happen to nucleotides A and T. This means that nucleotides C and G are more prone to be mutated by other nucleotides; nucleotides A and T are less prone to be mutated. In case of amino acid mutation, R is the most prone to be mutated by other amino acids in both mislocalized (15% of total mutation) and non-mislocalized (14% of total mutation) proteins. Our results also show that there is no correlation between hydrophobicity and number of mutation happen to an amino acid.