Nail-patella syndrome (NPS)

Nail-patella syndrome

Nail-patella syndrome (NPS; MIM 161200) is a dominantly inherited disorder characterized by dysplasia of the nails, hypoplastic or absent patellae, characteristic bony projections from the iliac wings, abnormalities of the elbows, and in some instances open angle glaucoma. Nephropathy and neurological or vasomotor symptoms can also be seen. This disorder is caused by loss of function mutations in LMX1B. The LMX1B gene codes for a homeodomain protein containing two N-terminal zinc binding protein domains and a C-terminal glutamine rich domain. This transcription factor plays an important role in dorsal-ventral patterning of the limb. It controls the initial trajectory of motor axons in the developing limb. It is also believed to regulate the expression of the COL4A3 and COL4A4 genes required for normal glomerular basement membrane morphogenesis.