Hello Gautam Kok!
You cannot add a row on the same sheet/chart as the 'n' is not the sum of your 0s, 1s, 2s or 3s.
What you can do is to create a calculated field which says : IF [Column]="ASNS" then 16 else if [Column]=.... END"
Once this is created, create a new sheet, drag the disease name as column and then drag the calculated field as text/label. You can hide the headers for the columns.
Then create a new dashboard and then put or stack the two separate sheets on top of each other.
Hope this helps. Thanks!