dedction

Disability U/s 80DD includes blindness, low vision, hearing impaired , mental illness and Mental retardness....

Disease for claiming exemption u/s 80 DDB should be a specified disease like Neurological deisease if the disability is certified to be 40% and above., cancer,aids, chronic renal failure, hemophilia , thalassaemia .

Basically disease and Disablity is interrelated...disability is caused mainly due to Diseases mentioned above

hope this will solve ur problem.if  not please feel free to ask and please be specific about what you exactly want to know

Regards

Vijay