Missing creases of distal finger joints as a diagnostic clue of nail-patella syndrome

Nail-patella syndrome (NPS, OMIM 161200) is an autosomal dominant disorder with a clinical characteristic tetrad consisting of fingernail dysplasia, hypoplastic or absent patellae, bony protuberances of the ilia (iliac horns) and dislocation of the radial head. Kidney involvement may lead to renal failure, and there is an increased risk for glaucoma. Clinical diagnostic skin clues are triangular lunulae especially on the thumbs which are highly predictive for the NPS. A less known but even more important sign is the absence of skin creases on the dorsal aspects of the distal interphalangeal joints. Even in patients with normal nails the absence of distal interphalangeal creases was noted. Less specific skin changes are webbing between digits, within the popliteal fossae, hyperextensible joints, absent or fragile nails and grooved nails and longitudinal ridging with splitting. With increasing costs in the health care system, it is important to recognize diseases by specific clinical findings which are often as predictive and precise as expensive technical investigations.