Types Of Mutations Quick Navigation Summary box for Types of Mutations The role of DNA sequences –a reminder Types of mutations Point mutations Substitution Insertions and deletions Consequences of point mutations and examples Missense mutations Sickle Cell Anaemia Nonsense mutations Duchenne muscular dystrophy Frameshift mutations Frequently Asked Questions What are the major types of mutations? What are point mutations? What are frameshift mutations? What is a nonsense mutation? Summary box for Types of Mutations Mutations occur through various mechanisms that can impact genes, chromosomes, and outcomes differently. Mutations can occur on a single nucleotide scale (at the level of point mutations), or on a much larger scale (where segments of whole chromosomes are affected. Substitution of nucleotides can be synonymous (silent) or non-synonymous (change amino acid). The resulting mutations can be missense (amino acid change in sequence) or nonsense (premature stop codon is encoded.