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At a glance

A rare autosomal dominant ectodermal dysplasia characterized by defects of the nail plates of the fingers (onychorrhexis) and toes (koilonychia). Familial hypodontia with normal hair and sweat gland function.


Witkop Syndrome; Dysplasia of Nails with Hypotonia.


Described by C. J. Witkop in 1965.


Estimated 1 to 2:10,000; condition is frequent among Dutch Mennonites in Canada.

Genetic inheritance

Autosomal dominant. Mapping found linkage in the region of the MSX1 locus on chromosome 4p16.


In a model of MSX1-deficient mice, histologic analysis confirmed that the MSX1 expression in mesenchyme of developing nail beds showed thinner nail and tooth development disrupted.


Nail dysplasia, hypoplastic dentition, normal hair, normal sweat and salivary gland function.

Clinical aspects

A variable number of teeth may be hypoplastic, the permanent incisors and second molars are most commonly affected. Complete adontia is rare. The nails are thin, centrally hollow, and brittle. Bilateral polycystic ovaries have been reported with the syndrome.

Precautions before anesthesia

Inspect dentition for teeth at risk of being dislodged during laryngoscopy and tracheal intubation. Special investigations as indicated by the proposed procedure.

Anesthetic considerations

The presence of hypodontia may be associated with a higher risk of dental damage during direct laryngoscopy. Otherwise, there are no specific considerations other than those relating to the proposed surgery.

Pharmacological implications

There are no known specific implications with this condition.


Ghaderi  F, Hekmat  S, Ghaderi  R, Fardaei  M: MSX1 mutation in witkop syndrome; a case report. Iran J Med Sci 38:191, 2013.  [PubMed: 24031111]
Murdoch-Kinch  C, Miles  D, Poon  C: Hypodontia and nail dysplasia syndrome. Oral Surg Oral Med Oral Pathol 75:403, 1993.  [PubMed: 8469557]
Witkop  CJ Jr: Genetic disease of the oral cavity, in Tiecke  RW (ed): Oral Pathology. New York, McGraw-Hill (pub), 1965, p 810.

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