Radial longitudinal deficiency (RLD) is a rare congenital condition where the radius bone in the forearm does not form properly. A congenital condition means that it existed at birth or even before birth. RLD causes the affected hand to be bent inward toward the thumb side of the forearm, often with limited movement.

In addition to the curve of the wrist and forearm, your child may have a missing or small thumb. The severity is different in each child.

RLD is also referred to as radial deficiency or radial club hand.