What is the difference between disease incidence and disease severity?
The incidence of disease is how frequent or widespread a disease is in the population. Severity is how bad and serious any particular disease is in a person.
Hungtington disease is a trinucleotide repeat genetic disorder, in which you have extra repeats of CAG in your gene coding for the hungtin protein. If you have more than 35 repeats you get the phenotype (symptoms), and it shows anticipation, which means that as the disease is passed on from generation to generation the repeats increase, hence the severity of the disease. It is quite rare, but the exact incidence is hard to estimate, because…
Most People with psoriatic arthritis will have some skin signs some where along the line This disease develops after skin psoriasis in approximately 70% of patients. the rest of the patients have either a simultaneous onset of skin and joint psoriasis or joint symptoms come on before any skin problem is noted. There is no relationship between the severity of the skin disease and the severity of the joint disease.