Rare dominant mutations in COL11A1, often disrupting a Gly-X-Y sequence, can cause Marshall (MRSHS) (OMIM #154780) or Stickler syndromes (STL2) (OMIM #604841) marked variously by facial anomalies, sensineural hearing loss, short stature, spondyloepiphyseal dysplasia, eye anomalies, ectodermal features, and scoliosis. The gene discussed is COL11A1; the disease is spondyloepiphyseal dysplasia.