<prompt> Following are listed as SpA spondyloahritis features exceptDactylitisEnthesitisHLA b27Cervical sprain  <response>: The spondyloahritides is a group of overlapping disorders that share ceain clinical features and genetic associations. These disorders include ankylosing spondylitis AS, reactive ahritis, psoriatic ahritis and spondylitis, enteropathic ahritis and spondylitis, juvenile onset spondyloahritis SpA, and undifferentiated SpA. The similarities in clinical manifestations and genetic predisposition suggest that these disorders share pathogenic mechanisms. Reference: Harrison;s Principles of Internal Medicine; 20th edition; Chapter 384; 