In addition to ARHR2 and GACI, loss-of-function pathogenic variants in ENPP1 can lead to progressive mixed hearing loss, ossification of the posterior longitudinal ligament, pseudoxanthoma elasticum (PXE), thrombocytopaenia, hypoglycaemia, neurologic and hepatic manifestations.6 This evidence concerns the gene ENPP1 and Pseudoxanthoma elasticum.