Prolyl endopeptidase-like (PREPL) deficiency (MIM# 616224) is a rare autosomal recessive inherited congenital myasthenic syndrome characterized by neonatal hypotonia, feeding problems, mild dysmorphism, and neuromuscular symptoms, followed by hyperphagia and obesity in later childhood. Some patients also exhibit growth deficits, sexual hormone deficiency, and cognitive impairments. This syndrome is caused by biallelic mutations in PREPL. To date, only one nucleotide deletion and seven small microdeletions in PREPL have been reported. Here we report a female patient with a novel homozygous frameshift mutation in PREPL (NM_006036.4, c.342delA:p.Val115Leufs*39). Her clinical features are similar to those of previously reported cases. The mutation is the first homozygous point mutation reported in humans.