[Coleus]

yes, you are right, a mutation is less genetic information and results in disease.

[VOA]

a mutation is less genetic information and results in disease.

Not always.
Sometimes the change in a single nucleotide will still code for the
same amino acid...hence you can (if lucky) have a mutation that
is "silent"...and would go unnoticed, but for sequencing of the
DNA sequence of the gene from other people without the mutation.