Missense, nonsense and frameshift variants change proteins in different ways

A replacement and an early stop are different outcomes

MedlinePlus describes a missense variant as a nucleotide substitution that replaces one amino acid with another. Whether that affects function depends on the particular change and protein context. [1]

A nonsense variant instead introduces a premature stop signal. The resulting product may be shortened, function poorly or be broken down. [1]

A frameshift changes how downstream bases are grouped

Protein-coding sequences are read in groups of three nucleotides. An insertion or deletion that changes this grouping can alter the downstream amino acid sequence and often disrupt protein function. [1]

Not every insertion or deletion shifts the frame. Interpret the actual variant and its coding context rather than assuming every DNA change has the same consequence. [1]

Name the mechanism before predicting the effect

Imagine one variant changes a single codon, while another shifts the reading frame. Both affect sequence, but they create different questions about the resulting protein and its function.

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