Nail-patella syndrome (Fong disease)

Abstract

A14-year-oldboypresentedtotheorthopedicclinicfornon-painful elbow deformities. Knee radiographs demonstratedsmall patellae (Fig. 1). Elbow radiographs showed disloca-tion of the right radial head (Fig. 2). Pelvic radiograph wasnormal. Physical exam revealed bilateral absence of nailson the thumb and index fingers. Nail-patella syndrome wasdiagnosed.Nail-patella syndrome(Fong dis ease, osteo-onychodysplasia)comprises four main components—nail dysplasia, hypo-plastic or absent patellae, hypoplastic radial head and/orcapitella (with or without dislocation), and iliac horns [1].Iliac horns, though pathognomonic, are present in only 70–80% of cases. Complications include limited elbowextension and patellar subluxation. Thirty percent of casesare associated with glomerulonephritis or nephrotic syn-drome. Radiographs and physical exam are diagnostic andcan exclude other diagnoses with small patellae, includingthe small patella syndrome, Kuskokwim syndrome, andCoffin-Siris syndrome [2].References