To date, only one mutation, a frameshift homozygous mutation (c.76_98del; p.E26RfsX68) within CPE, has been described in a patient with morbid obesity, type 2 diabetes mellitus, intellectual disability and hypogonadotropic hypogonadism; this is not listed as a specific Mendelian syndrome in the Online Mendelian Inheritance in Man (OMIM) database (10). Here, CPE is linked to Intellectual disability.