Nail–patella syndrome

Nail–patella syndrome is a rare genetic disorder that results in small, poorly developed or deformed nails (especially of thumbs) and — next in order/frequency — hypoplastic kneecaps. A unique feature of this syndrome is the usually triangular — rather than semicircular, as in healthy individuals — lunulae at the base of the fingernails. But nail-patella syndrome can also affect many other areas of the body, such as the elbows, chest, hips and others. The name "nail–patella" can be very misleading, because the syndrome usually is associated simultaneously with many various areas of the body, including even the production of certain proteins. The severity of these effects varies depending on the individual. It is also referred to as iliac horn syndrome, hereditary onychoosteodysplasia (HOOD syndrome), Fong disease or Turner–Kieser syndrome. This syndrome is caused by mutations in the LMX1B gene (see below).

Diagnosis of NPS can be made at birth but is common for it to remain undiagnosed for several generations. While there is no cure available for NPS, treatment is available and recommended.

In the international medical classification (ICD), the syndrome is included in the category Q87.2 — Congenital malformation syndromes predominantly involving limbs.