Children with Williams syndrome, a genetic disorder that causes both physical and mental developmental problems, typically have a broad forehead, chubby cheeks, wide and full lips, and an upturned nose, according to Genetics Home Reference. Older children and adults with the syndrome tend to have a long, gaunt face.
Dental problems are not uncommon in those with Williams syndrome. Small, crooked and widely spaced teeth are common, as are missing teeth. Other symptoms related to physical appearance include short height, a sunken chest, bent pinky fingers and lack of muscle tone, says Healthline. Those with the condition also have distinct personality traits, such as a dislike for physical contact.