Holt-Oram syndrome

Holt-Oram syndrome is an autosomal dominant disorder that affects the bones of the arms and hands, the upper limbs, and often causes heart problems as well. It is also called atrio-digital syndrome, atriodigital dysplasia, cardiac-limb syndrome, heart-hand syndrome type 1, ventriculo-radial syndrome and by the initials HOS. The syndrome may include an absent radial bone in the forearm, an atrial septal defect, which is an opening in the wall between the upper chambers of the heart, or heart block, a disturbance in the conduction of the heartbeat. It affects approximately one in 100,000 people. The many alternative names show how the condition has been described from both a cardiac and a limb point of view, and they all refer to the same combination of upper limb and heart findings.