Mantel novel about current disorder (7)
I believe the answer is:
ailment
'disorder' is the definition.
(I know that disorder can be written as ailment)
'mantel novel about current' is the wordplay.
'novel' indicates an anagram (letters in a new or novel order).
'about' means one lot of letters goes inside another.
'current' becomes 'I' (symbol for electric current).
'mantel' is an anagram of 'alment'.
'alment' placed around 'i' is 'AILMENT'.
(Other definitions for ailment that I've seen before include "I lament (anag.)" , "Malady" , "Sickness" , "Bodily disorder or disease" , "Tim Alen has an odd indisposition." .)