Pathogenic COL2A1 variants have been associated with varying skeletal dysplasias, including achondrogenesis and hypochondrogenesis (OMIM 200610) [19], while pathogenic PCDH19 variants have been associated with a female-restricted form of sporadic infantile epileptic encephalopathy (OMIM 300088) [20]. This evidence concerns the gene COL2A1 and genetic developmental and epileptic encephalopathy.