Absent patella

A rare genetic malformation where the kneecap is absent or reduced.

The mechanisms underlying the different manifestations and severity of the symptoms in this disorder remain uncertain.

NPS is known to be an autosomal dominant hereditary disease.
A genetic abnormality is believed to lead to altered connective tissue metabolism with widespread structural defects in collagen.
Abnormal collagen deposition in the glomeruli probably causes the nephropathy associated with NPS.