PQBP1 and Renpenning syndrome: Mutations in the PQBP1 gene have been identified in patients suffering from different disorders, including Sutherland–Haan syndrome, Golabi–Ito–Hall syndrome, Hamel cerebro-palato-cardiac syndrome, Porteous syndrome and MRX55, which are collectively called the Renpenning syndrome spectrum [8,9,10,11].