<prompt> 40 years patient having arthritis of PIP and DIP along with a carpometacarpal joint of the thumb and sparing of the wrist and metacarpophalangeal joint, most likely diagnosis is -Rheumatoid arthritisOsteoarthritisPsoriatic arthritisPseudogout  <response>: Involvement of PIP, DIP and 1st Carpometacarpal joint Carpometacarpal joint of thumb with sparing of the wrist and the metacarpophalangeal joint is characteristic of OA. 