what is missense mutation

A missense mutation is a type of point mutation or single base mutation that replaces one nucleotide of the codon on the DNA with other nucleotides, which eventually results in coding a different amino acid in the protein. This type of mutation is a type of nonsynonymous substitution in a DNA sequence. Missense mutations can be caused spontaneously or due to any mutagen. Usually, missense mutation occurs spontaneously during DNA replication, wherein point mutations within a DNA sequence are seen to replace a nucleotide at a particular DNA sequence. However, mutagens like Reactive oxygen species (ROS), X-rays, and UV radiations may induce missense mutations. Missense mutations can render the resulting protein nonfunctional, and such mutations are responsible for human diseases such as Epidermolysis bullosa, sickle-cell disease, SOD1 mediated ALS, and a substantial number of cancers. Depending on which amino acid it codes for, missense mutations can be conservative (i.e., the resulting protein is functional) or nonconservative (i.e., the resulting protein is non-functional) .