Nail-patella syndrome is a rare inherited disorder of mesenchymal tissue characterized by abnormalities of bones, joints, fingernails and toenails, and kidneys. Diagnosis is based on clinical presentation and genetic testing. There is no specific treatment, but angiotensin-converting enzyme inhibitors may be given for proteinuria and hypertension, and kidney replacement therapy or kidney transplantation is performed when indicated.
Nail-patella syndrome is an autosomal dominant disorder caused by a mutation in the LMX1B gene, which plays an important role in limb and kidney development.
Symptoms and Signs of Nail-Patella Syndrome
There is bilateral hypoplasia, dysplasia, or absence of the patella; subluxation of the radial head at the elbows; and bilateral accessory iliac horns. Bone fractures may occur.
Fingernails and toenails are absent, hypoplastic, or dystrophic, with pitting and ridges.
Renal dysfunction occurs in 30 to 50% of patients due to focal segmental glomerular deposits of IgM and C3. Proteinuria, hypertension, and hematuria are the most common manifestations, and up to 15% of patients with renal involvement slowly progress to kidney failure (1).
Patients may develop glaucoma.
Symptoms and signs reference
1. Sweeney E, Hoover-Fong JE, McIntosh I. Nail-Patella Syndrome. 2003 May 31 [Updated 2023 Dec 14]. In: Adam MP, Feldman J, Mirzaa GM, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2025.
Diagnosis of Nail-Patella Syndrome
History and physical examination
Genetic testing
Sometimes extremity and pelvic radiograph or kidney biopsy
Diagnosis of nail-patella syndrome is suggested clinically; sometimes kidney biopsy and bone radiographs are indicated, which are diagnostic.
LMX1B mutation analysis is possible, including for prenatal diagnosis, but the type of mutation does not usually predict clinical severity (1). LMXB1 mutations affecting only the kidney have been described.
Diagnosis reference
1. Harita Y, Kitanaka S, Isojima T, Ashida A, Hattori M. Spectrum of LMX1B mutations: from nail-patella syndrome to isolated nephropathy. Pediatr Nephrol. 2017;32(10):1845-1850. doi:10.1007/s00467-016-3462-x
Treatment of Nail-Patella Syndrome
Angiotensin-converting enzyme (ACE) inhibitors for proteinuria and hypertension
Kidney replacement therapy or transplantation when indicated
There is no specific treatment for nail-patella syndrome, but proteinuria and hypertension can be treated with ACE inhibitors (1).
When indicated, kidney replacement therapy or kidney transplantation may be necessary; transplantation typically has favorable outcomes (1).
Treatment reference
1. Sweeney E, Hoover-Fong JE, McIntosh I. Nail-Patella Syndrome. 2003 May 31 [Updated 2023 Dec 14]. In: Adam MP, Feldman J, Mirzaa GM, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2025.
