Zhang Cheng, a 16-year-old from China, has been diagnosed with congenital ectodermal dysplasia, which affects less than 0.001% of children born. This disease is genetic and causes minimal to no growth of teeth in the mouth. Continue reading for another case.

Simon Cullen, 13, and his brother George, 11 also suffer from the rare genetic condition known as Hypohidrotic Ectodermal Dysplasia (HED). Simon, who did not grow any teeth at all until he was five, struggles to chew many foods and the only meat he can eat is sausages. Simon will have false teeth fitted using bone from his leg. George is two years younger and already has more teeth than Simon, but their parents, Mandy and John, are hoping that an operation will help their eldest son.

[Sources 1 | 2]