Familial absence of the patella.
D000293:Adolescent; D000013:Congenital Abnormalities / Q000235:genetics; D003937:Diagnosis, Differential; D006801:Humans; D007717:Knee / Q000000981:diagnostic imaging; D008297:Male; D009261:Nail-Patella Syndrome / Q000175:diagnosis; D010329:Patella / Q000002:abnormalities*; D011859:Radiography