EXTL3 dysfunction identified as a driver of aberrant bone development in severe familial ankylosing spondylitis.
This study identifies EXTL3 as a genetic modifier of structural severity in AS and reveals a previously unrecognised role for HS metabolism in pathological ossification, which supports a model in which HLA-B27 primarily confers disease susceptibility, whereas rare variants such as EXTL3 contribute to structural progres...