Visual Diagnosis: Dysplastic Nails and Elbows in a 15-year-old Boy

Presentation

A 15-year-old boy presents to the office for a routine sports physical. During the examination his mother mentions that the patient has unusual fingernails and bony deformity of the elbows, both findings present since birth. His mother believes that a nutritional deficiency may be causing the abnormalities. He denies any other musculoskeletal deformities, including of the lower extremities and chest wall. The patient reports no medical history and, despite the deformity, is very active in sports, with no limitations. On further questioning it is reported that several family members on the mother’s paternal side have similar nail findings. His mother and his brother have nail involvement solely of their thumbs.

On physical examination, bilateral radial head subluxation is evident. The patient’s arms are deviated laterally (Fig 1). He has limited extension at the elbows, with some limitation of pronation and supination (Fig 2). The patellae are normal on inspection. Examination of the nails reveals incomplete development, or partial anonychia of bilateral thumbs (Fig 3), as well as triangular lunulae with the apex pointing distally. A central longitudinal depression is found on several digits, in addition to small nails or micronychia, hypoplasia of the nail plate, and longitudinal ridges (Fig 4). The toe nails are less severely affected. A clinical diagnosis is made. A urinalysis is performed, and the results are within normal limits. He is referred to orthopedics and ophthalmology for further evaluation.