Nail-patella syndrome (NPS; OMIM 161200) is a well-known autosomal dominant condition characterized by nail dysplasia, patellar aplasia-hypoplasia, arthrodysplasia of the elbows, iliac horns, and nephropathy. Recent reports indicate that open-angle glaucoma (OAG) may also cosegregate with NPS. One of the first chromosomal linkages identified in humans is between the NPS locus and the ABO blood group on chromosome 9. LMX1B, located on band 9q34.1, is an LIM-homeodomain transcription factor required for the normal development of dorsal limb structures, the glomerular basement membrane, the anterior segment of the eye, and dopaminergic and serotonergic neurons. Heterozygous loss-of-function mutations in LMX1B cause NPS.
* Proteinuria: This is the first sign of renal involvement. The patient may remain asymptomatic or eventually develop ESRD.
* Hypoplastic nails: Absence of the thumbnail is the most common nail pattern. Other nails may be less fragile.
* Knee abnormalities: Some patients report recurrent dislocation or arthritis, which may necessitate patellar replacement.
* Limited ROM in the elbows
* Decreased pronation or supination of the elbows, appearing unilaterally or bilaterally
* Hypoplastic radial head
Suzanne M Carter, MS & Susan J Gross, MD, FRCS(C), FACOG, FACMG Updated: Feb 13, 2007