title: In children with autoimmune thyroid diseases the association with Down syndrome can modify the clustering of extra-thyroidal autoimmune disorders.
abstract: BACKGROUND
  It is known that the association with Down syndrome (DS) can affect the phenotypic expression of autoimmune thyroid diseases (AITDs), whilst is unknown whether the clustering of extra-thyroidal autoimmune diseases (ETADs) may also be atypical in DS children.
  
  
  METHODS
  The aim of this study was to investigate the clustering of ETADs in 832 children with AITDs divided in two groups with or without DS (A and B, respectively) and in four subgroups of patients aged either <6 or ≥6 years.
  
  
  RESULTS
  The rate of children with ETADs was significantly higher in Group A; in particular, alopecia areata (p=0.00001) and vitiligo (p=0.00001) were found more often in Group A irrespective of age, whilst the distribution of T1 diabetes mellitus was not different in the two groups. Celiac disease prevalence was significantly higher in DS patients only in the older subgroup.
  
  
  CONCLUSIONS
  The association with DS may be able to modify the clustering of ETADs in the children with AITDs by favoring the aggregation of some specific diseases such as alopecia areata and vitiligo.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Aversa
authors.forename: Mariella
authors.initials: M
authors.lastname: Valenzise
authors.forename: Andrea
authors.initials: A
authors.lastname: Corrias
authors.forename: Mariacarolina
authors.initials: M
authors.lastname: Salerno
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Iughetti
authors.forename: Daniele
authors.initials: D
authors.lastname: Tessaris
authors.forename: Donatella
authors.initials: D
authors.lastname: Capalbo
authors.forename: Barbara
authors.initials: B
authors.lastname: Predieri
authors.forename: Filippo
authors.initials: F
authors.lastname: De Luca
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Wasniewska
mesh_terms: D000506:Alopecia Areata / Q000453:epidemiology* / Q000209:etiology; D001327:Autoimmune Diseases / Q000150:complications*; D002446:Celiac Disease / Q000453:epidemiology* / Q000209:etiology; D002648:Child; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology* / Q000209:etiology; D004314:Down Syndrome / Q000150:complications*; D005260:Female; D005500:Follow-Up Studies; D050031:Hashimoto Disease / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D015995:Prevalence; D011379:Prognosis; D014820:Vitiligo / Q000453:epidemiology* / Q000209:etiology