A point mutation is a mutation within DNA sequence when a single nucleotide is changed (substitued, deleted, added). They can have various effects depending on the type of point mutation. For example, nonsense mutations are point mutations that result in a premature stop codon. UAC codon codes for the tyrosine amino acid, while UAG is stop codon. A s a consequence, protein product is usually unfunctional because it is incomplete.
Nonsense mutations can cause genetic disorders (e.g. thalassemia).
