Leri pleonosteosis is a condition marked by unique changes in the fingers and toes. People with this condition often have broadening and deformity of the thumbs and great toes, which may appear in a spade-shaped form due to valgus positioning. They may also experience stiffness in their joints and have a shorter stature. Some individuals have facial features described as mongoloid facies. In addition to the digital changes, there may be other skeletal differences. These include flexion contracture of the finger joints, genu recurvatum (backward bending of the knees), enlargement of the posterior neural arches of the cervical vertebrae, and thickening of the fascia in the palms and forearms. The condition appears in a few multigenerational families and follows an autosomal dominant pattern of inheritance.

Common signs and symptoms of Leri pleonosteosis include broad and deformed thumbs and great toes, which may have a spade-shaped appearance due to their valgus positioning. There is often flexion contracture affecting the finger joints, along with a general limitation in joint mobility. People with this condition may also have a shorter stature and distinctive facial features. Additional skeletal changes such as genu recurvatum, enlargement of parts of the cervical vertebrae, and thickened fascia in the palms and forearms have been noted.

Leri pleonosteosis is caused by genetic changes and is inherited in an autosomal dominant manner. This means that a change in one copy of the gene, such as DUP8Q22.1, can cause the condition. The genetic nature of the syndrome explains why it is seen in multigenerational families.