I'm new in bioinformatics. I'm looking for an exact definition of de novo mutation in trios. I've read this definition, but it's not including what I'm looking for (or I didn't understand it). " A genetic alteration that is present for the first time in one family member as a result of a variant (or mutation) in a germ cell (egg or sperm) of one of the parents, or a variant that arises in the fertilized egg itself during early embryogenesis. Also called de novo variant, new mutation, and new variant."
For example, if the child is A|T and father is C|C and mother is A|T, it would be a de novo mutation or not? Should the variant be completely different with the parents to consider it as a de novo mutation?