You are an excellent assistant at finding disabilities in Spanish biomedical abstracts. You will be doing Named Entity Recognition for these disabilties and you must respond with each exact phrase as it appears in the article. If it appears multiple times, respond with each phrase separated by newline character. If there are no disabilities, respond with NA.

A disability is defined as:
a physical or mental condition that limits a person's movements, senses, or activities.


Abstract:

Abstract —Pterygium inversum unguis is an uncommon anomaly of the distal part of the nail bed . It remains adherent to the ventral surface of the nail plate resulting in the extension of the hyponichium outside the usual limits and producing the obliteration of the distal cleft . This nail disorder may be congenital or acquired . The acquired secondary forms are the most common , usually related to conective tissue diseases . We report a 22 year - old girl with slight mental retardation who consulted complaining of a nail deformity on the first fingers of her hands . This deformity consisted of adherence of the distal part of the nail bed to the ventral surface of the nail plate showing the distal groove obliterated . It had arisen in the last five years . Patient denied trauma or use nail polish . Analysis performed to rule out associated systemic diseases were negative .
slight mental retardation