title: High prevalence of autoimmune disease in the rare inflammatory bone disorder sternocostoclavicular hyperostosis: survey of a Dutch cohort.
abstract: Sternocostoclavicular hyperostosis (SCCH; ORPHA178311) is a rare inflammatory disorder of the axial skeleton, the precise pathophysiology of which remains to be established. We addressed the potential association of SCCH with autoimmune processes by evaluating the lifetime prevalence of autoimmune disease in 70 patients with adult-onset SCCH and 518 SCCH-unaffected first-degree relatives (parents, siblings and children). Danish hospital registry data for autoimmune diseases were used as reference data.
  
  
  
  The mean age of interviewed patients was 56.3 years (range 26-80 years) and 86% were female. Interviewed patients belonged to 63 families, with four families having clusters of 2-3 patients. A diagnosis of at least one autoimmune disease was reported in 20 SCCH patients (29%) and in 47 relatives (9.1%), compared to an estimated 3.9% prevalence of autoimmune disease in the Danish reference population. A diversity of autoimmune diseases was reported in SCCH patients and relatives, most frequently psoriasis vulgaris (14%). Palmoplantar pustulosis was reported by 28 patients (40%). In SCCH patients, inclusion of palmoplantar pustulosis as putative autoimmune disease increased the overall prevalence to 54%.
  
  
  
  The high prevalence of autoimmune disease in patients with sternocostoclavicular hyperostosis and their first-degree relatives suggests that autoimmunity may play a role in the still elusive pathophysiology of the intriguing osteogenic response to inflammation observed in this rare bone disorder.
authors.affiliation: Department of Medicine, Division of Endocrinology & Centre for Bone Quality, Leiden University Medical Center, Albinusdreef 2, Leiden, 2333ZA, The Netherlands.
authors.forename: Pieter A
authors.initials: PA
authors.lastname: Valkema
authors.affiliation: Department of Medicine, Division of Endocrinology & Centre for Bone Quality, Leiden University Medical Center, Albinusdreef 2, Leiden, 2333ZA, The Netherlands.|Department of Public Health and Primary Care, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Clare H
authors.initials: CH
authors.lastname: Luymes
authors.affiliation: Department of Medicine, Division of Endocrinology & Centre for Bone Quality, Leiden University Medical Center, Albinusdreef 2, Leiden, 2333ZA, The Netherlands.
authors.forename: Janneke E
authors.initials: JE
authors.lastname: Witteveen
authors.affiliation: Department of Medical Statistics and Bioinformatics, Leiden University Medical Center, Leiden, The Netherlands.|Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Saskia
authors.initials: S
authors.lastname: le Cessie
authors.affiliation: Department of Medicine, Division of Endocrinology & Centre for Bone Quality, Leiden University Medical Center, Albinusdreef 2, Leiden, 2333ZA, The Netherlands.
authors.forename: Natasha M
authors.initials: NM
authors.lastname: Appelman-Dijkstra
authors.affiliation: Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Pancras C W
authors.initials: PC
authors.lastname: Hogendoorn
authors.affiliation: Department of Medicine, Division of Endocrinology & Centre for Bone Quality, Leiden University Medical Center, Albinusdreef 2, Leiden, 2333ZA, The Netherlands. N.A.T.Hamdy@lumc.nl.
authors.forename: Neveen A T
authors.initials: NA
authors.lastname: Hamdy
mesh_terms: D020083:Acquired Hyperostosis Syndrome / Q000453:epidemiology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000453:epidemiology*; D001847:Bone Diseases / Q000453:epidemiology*; D015331:Cohort Studies; D006801:Humans; D015218:Hyperostosis, Sternocostoclavicular / Q000453:epidemiology; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D015995:Prevalence; D011565:Psoriasis / Q000453:epidemiology; D035583:Rare Diseases / Q000453:epidemiology*
keywords: Autoimmune disease; Inflammatory disease; Palmoplantar pustulosis; Prevalence; SAPHO syndrome; Sternocostoclavicular hyperostosis; Survey