megalonychosis

macronychia

A condition in which the finger- and/or toenails are larger than normal, usually wider than they are long, due to shortening of the bone of the distal phalanx.
 
Aetiology
Idiopathic, Proteus syndrome, Rubinstein Taybi syndrome.

megalonychosis

(mĕg′ă-lō″nĭ-kō′sĭs) [″ + onyx, nail]

Hypertrophy of the nails.