Prolyl endopeptidase-like (PREPL) deficiency (MIM 616224) is a very rare congenital disorder characterized by neonatal hypotonia and feeding difficulties, ptosis, neuromuscular symptoms, cognitive impairments, growth hormone deficiency, short stature, and hypergonadotropic hypogonadism. Here, PREP is linked to myasthenic syndrome, congenital, 22.