Some of the information here was borrowed from http://www.nailpatella.org/ Nail Patella Syndrome (also called Fong's Disease, Hereditary Onycho-Osteodysplasia ['HOOD'] is characterized by several typical abnormalities of the arms and legs as well as kidney disease and glaucoma. It has been recognized as a hereditary condition for over 100 years and is inherited in an autosomal dominant manner. That is, the risk of transmission is 50% per pregnancy, irrespective of gender (just like flipping a coin). Approximately 20% of cases are sporadic, being the result of a new mutation. The incidence is approximately 1 in 50,000 and occurs throughout the world in all ethnic groups
This is a scan of my hand (ever try to scan your hands?? you have to be a contortionist!) My index finger is a good example of what a NPS fingernail looks like.
I didn't know what NPS was until January of 2001. I was bored on New Years and was randomly looking stuff up on Google. I put "fingernail birth defects" into the search engine and everything that came up mentioned Nail Patella Syndrome.