Anonychia Explained

Anonychia
Field:	Dermatology

Anonychia is the failure to form fingernails or toenails.^[1]

It is an anomaly which may be the result of a congenital ectodermal defect, ichthyosis, severe infection, severe allergic contact dermatitis, self-inflicted trauma, Raynaud phenomenon, lichen planus, epidermolysis bullosa, or severe exfoliative diseases.^[2]

Cause

This is rare and is usually due to mutations in the R-spondin 4 (RSPO4) gene which is located on the short arm of chromosome 20 (20p13).^[3]

See also

• List of cutaneous conditions

Notes and References

1. Book: MacGilchrist . Claire . Burrow . J. Gordon . Rome . Keith . Padhiar . Nat . Neale's Disorders of the Foot and Ankle . 2020 . Elsevier . 978-0-7020-6504-0 . 52 . 9th . https://books.google.com/books?id=2KPsDwAAQBAJ&pg=PA52 . en . 3. The skin and nails in podiatry .
2. Book: James . William D. . Elston . Dirk . Treat . James R. . Rosenbach . Misha A. . Neuhaus . Isaac . Andrews' Diseases of the Skin: Clinical Dermatology . 2020 . Elsevier . Edinburgh . 978-0-323-54753-6 . 782 . 13th . https://books.google.com/books?id=UEaEDwAAQBAJ&pg=PA782 . en . 33. Diseases of the skin appendages .
3. Khan TN, Klar J, Nawaz S, Jameel M, Tariq M, Malik NA, Baig SM, Dahl N (2012) Novel missense mutation in the RSPO4 gene in congenital hyponychia and evidence for a polymorphic initiation codon (p.M1I). BMC Med Genet 13(1):120