In the majority of cases, hypodontia has a genetic basis.
Tooth agenesis is found more commonly among individuals
related to hypodontia patients than in the population in
general56 identifying it as a genetic disease. An exhaustive
study on a Swedish family with 685 family members, including
171 probands affected with hypodontia, showed that
hypodontia involving permanent teeth is primarily
determined by genetic factor(s)38. The frequency of
hypodontia among races varies30,78 and greater concordance
of hypodontia is apparent in identical twins than nonidentical79-
80 with no environmental etiology apparent in