A genetic disorder characterized by the absence of several teeth at birth and abnormalities of the nails. The disorder is also known as hypodontia and nail dysgenesis or Witkop syndrome (TNS). It was first described by Dr. Carl Witkop in 1965.
The tooth and nail defects in the syndrome are highly variable. The number and type of congenitally missing permanent and/or primary teeth vary. The nails are thin, slow-growing, brittle and spoon-shaped (koilonychia). Toenails are usually more severely affected than the fingernails. In rare cases, the nails spontaneously separate from the nail beds or are absent at birth.
About 1 in 1,000 people has TNS. It is inherited as an autosomal dominant trait capable of affecting males and females and multiple generations.
The gene responsible for TNS was identified in 2001 and is termed MSX1. A nonsense mutation in this gene in TNS appears to encode a protein that is completely nonfunctional. Another nonsense mutation in MSX1 has been associated with oral clefting in addition to tooth agenesis (absence of teeth).
- Syndrome, toxic shock
A grave condition occurring predominantly in menstruating women using tampons. Toxic shock is characterized by a highly toxic state (with sudden high fever, vomiting, diarrhea, muscle aching) followed by low blood pressure (hypotension) which can lead to shock (and death). There may be a rash resembling sunburn with peeling of skin. The Channing Laboratory in […]
- Syndrome, trisomy 18
There are three instead of the normal two chromosomes #18. Children with this condition have multiple malformations and mental retardation due to the extra chromosome #18. The children characteristically have low birth weight, small head (microcephaly), small jaw (micrognathia), malformations of the heart and kidneys, clenched fists with abnormal finger positioning, and malformed feet. The […]
- Syndrome, Usher
A genetic disorder characterized by hearing impairment and an eye disorder called retinitis pigmentosa in which vision worsens over time. Some people with Usher syndrome also have balance problems. It is the most common disease that compromises both hearing and vision. More than half of all deaf-blind people have Usher syndrome. The syndrome is passed […]
- Syndrome, von Hippel-Lindau
See Von Hippel-Lindau syndrome.
- Syndrome, Werner
A premature aging disease that begins in adolescence or early in adulthood and results in apparent old age by 30-40 years of age. The characteristic features of Werner syndrome include short stature, premature graying and balding, wizened face, beaked nose, cataracts, scleroderma-like skin changes (especially in the extremities), subcutaneous calcification (deposits of calcium beneath the […]