The most common symptom of hypodontia is being born missing one to six teeth. The missing teeth can occur anywhere in your mouth — except your wisdom teeth. Hypodontia can affect primary (baby) teeth or permanent (adult) teeth. People with hypodontia may also have existing teeth that are peg-shaped or smaller than average. They may also have gaps and spaces between their existing teeth. Hypodontia can also be a symptom of other genetic disorders. Some people with hypodontia may also develop symptoms of ectodermal dysplasias. People with ectodermal dysplasia may have: Nail abnormalities. Thinning hair. Poor hearing. Poor vision. A lack of sweat glands.