COL27A1 and Global developmental delay: Given the phenotypic overlap but increased severity and additional features not observed or reported to date in the majority of the Puerto Rican STLS patients, such as congenital or early onset hearing loss, speech and developmental delay, and novel radiographic features including tall vertebral bodies, long vertebral pedicles, and shallow glenoid fossae (Fig. 1), we propose these to represent an allelic series of COL27opathies with potentially a broader phenotype spectrum due to biallelic function altering variants in COL27A1 and allowing a more complete clinical synopsis of this locus.