NECTAR classifies genetic mutations into 14 classes based on the following three criteria:
I) consequence types II) degree of damaging effect III) is the mutation novel?

I. Mutation Consequence Types

This category is basically built on the basis of 'predicted variation consequences' of Ensembl Variations with the help of Ensembl Variation API.
There are four levels:
Click to see in details.

II. Degree of Damaging Effects (level b only)

how to measure 'damaging effects'? This category is for non-synonymous mutations (b) where amino acids are changed or deleted. This is to answer 'how deleterious those missense and inframe deletion mutations are' by investigating structural and functional effects based on the three criteria as shown in the Venn diagram.
There are four classes:
  • 3: satisfying all the three coditions
  • 2: satisfying any of the two conditions
  • 1: satisfying any of one condition
  • 0: satysfying none
Based on I and II above, there could be 7 possible combinations for a mutation class, which make the mutation signal system.

III. Is the Mutation Novel?

Finally, NECTAR tells you whether the mutation has been reported previously based on dbSNP and HGMD. It is encoded 1 for novel (not reported) and 0 for seen, which is added as the last digit to the mutation code. For example, a mutaion of 'a11' stands for: