Para-legal lost an article, mutated, and got a disease (8)
I believe the answer is:
pellagra
'disease' is the definition.
(pellagra is a kind of health problem)
'para-legal lost an article mutated' is the wordplay.
'lost' is a deletion indicator.
'an article' becomes 'a' (the indefinite article in English).
'mutated' indicates an anagram.
'para'+'legal'='paralegal'
'paralegal' with 'a' taken away is 'pralegal'.
'pralegal' is an anagram of 'PELLAGRA'.
'and got a' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for pellagra that I've seen before include "ill with this?" , "Wasting disease, caused by a Vitamin B deficiency" , "Itching" .)