title: Clinical study of twenty-nail dystrophy in Korea.
abstract: BACKGROUND
  Twenty-nail dystrophy (TND) is an idiopathic and non-congenital nail dystrophy that is characterized by excess longitudinal ridges and loss of luster in multiple nail plates. There are a few studies on TND.
  
  
  METHODS
  In order to investigate the demographic and clinical characteristics of patients with TND in Korea, a retrospective study was performed. Eighty-eight patients were diagnosed with TND from February 1, 2003, to April 30, 2010.
  
  
  RESULTS
  In this study, morphology of TND was clinically divided as atrophic, hypertrophic, pitting dominant, shallow fissure-dominant, and deep fissure-dominant types. The patients consisted of 33 males and 55 females. The proportions of subtype and gender predominance showed differences between the child-adolescent-onset TND (20 cases) and the adult-onset TND (68 cases).
  
  
  CONCLUSIONS
  The clinical data of this study contribute to our understanding of TND.
authors.affiliation: Department of Dermatology, St Mary's Hospital, College of Medicine, Catholic University of Korea, Seoul, Korea.
authors.forename: Young Bok
authors.initials: YB
authors.lastname: Lee
authors.forename: Min Seok
authors.initials: MS
authors.lastname: Cheon
authors.forename: Hyun Jeong
authors.initials: HJ
authors.lastname: Park
authors.forename: Baik Kee
authors.initials: BK
authors.lastname: Cho
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009264:Nails, Malformed / Q000453:epidemiology / Q000473:pathology*; D012189:Retrospective Studies; D055815:Young Adult