Genetic diseases are caused by gene mutations that are inherited from one or both parents. Certain genetic diseases can cause abnormalities in the teeth, affecting the rate of development of primary (baby) and secondary (adult) teeth or their physical characteristics. Often, these genetic diseases affect the normal growth and health of other parts of the body, as well.
Amelogenesis imperfecta is a genetic condition that causes teeth to be abnormally small or discolored. Teeth are also likely to be pitted or grooved and more susceptible to being worn down and breaking. There are at least 14 forms of the condition, each with its own characteristic display of tooth abnormalities and form of genetic inheritance, according to the National Institutes of Health (NIH). Amelogenesis imperfecta is caused by mutations to the AMELX, ENAM and MMP20 genes and affects an estimated one in 14,000 people in the United States.
Dentinogenesis imperfecta is a genetic disorder that interferes with normal tooth development. It affects approximately one in 6,000 to 8,000 people, according to the National Institute of Health. There are three types of dentinogenesis imperfecta. Type I occurs in individuals who have another inherited disorder called osteogenesis imperfect (causes brittle bones), whereas type II and type III occur in those without other genetic disorders. Some researchers believe types II and III are part of a single disorder along with another condition called dentin dysplasia type II, which primarily affects baby teeth more than adult teeth. General symptoms of dentinogenesis imperfecta include tooth discoloration (blue-gray or yellowish-brown), tooth translucency and weaker than normal teeth which make them prone to erosion, breakage and loss.
A rare chromosomal condition that affects one in 18,000 to 50,000 males, 48,XXYY syndrome interferes with sexual development, causing reduced height, facial and body hair, increased risk of breast enlargement, infertility, progressive tremor and other serious medical problems that develop increasingly later in life. Dental problems are also common. According to the NIH, the delayed appearance of primary and secondary teeth, crowded and/or misaligned teeth, numerous cavities and thin tooth enamel often accompany the disorder.
Hypohidrotic Ectodermal Dysplasia
Hypohidrotic ectodermal dysplasia is an inherited condition affecting approximately one in 17,000 people worldwide that causes abnormalities of the skin, nails, hair, sweat glands and teeth. Those with the condition usually have absent teeth (hypodontia) or malformed teeth. It is common for malformed teeth to appear small and pointed. According to the NIH, approximately 70 percent of carriers of the gene that causes the condition (those with only one, but not both, recessive mutated genes) display symptoms, including some missing or abnormal teeth, sparse hair and some sweat gland dysfunction.
Oculodentodigital dysplasia is an extremely rare genetic disease (with fewer than 1,000 people diagnosed worldwide) that affects the eyes, fingers and teeth. Common tooth abnormalities include small or missing teeth, numerous cavities, weak enamel and early tooth loss, according to the NIH. The condition can also lead to small eyes, vision loss, webbed skin and neurological problems. An autosomal dominant disorder, it develops when only one mutated gene is inherited from a parent.
Recombinant 8 Syndrome
Recombinant 8 syndrome is a rare disease of unknown incidence primarily affecting an Hispanic population descending from the San Luis Valley of Colorado and Northern New Mexico. Inherited in an autosomal dominant pattern, recombinant 8 syndrome causes distinctive facial abnormalities, moderate to severe intellectual disability and heart and urinary tract problems. Abnormal teeth, an overgrowth of gums, small chin, thin upper lip and downturned mouth are all associated with the condition, according to the NIH.