European Journal of Pediatrics

, Volume 169, Issue 11, pp 1417–1421 | Cite as

Fibrodysplasia ossificans progressiva (FOP): watch the great toes!

  • Mutlu Kartal-KaessEmail author
  • Eileen M. Shore
  • Meiqi Xu
  • Ludwig Schwering
  • Markus Uhl
  • Rudolf Korinthenberg
  • Charlotte Niemeyer
  • Frederick S. Kaplan
  • Melchior Lauten
Short Report


Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disorder and the most disabling condition of heterotopic (extraskeletal) ossification in humans. Extraskeletal bone formation associated with inflammation preceding the osseous conversion usually begins in the first decade, predominantly in the head, neck, and shoulders. All patients have malformed great toes. Most patients have a spontaneous mutation of the ACVR1 gene. We report a 17-year-old girl with malformed great toes who had her first episode of heterotopic ossification and impaired mobility of the left hip at the age of 13 years. No inflammatory fibroproliferative masses preceded the onset of heterotopic ossification. Radiographic studies demonstrated myositis ossificans, but failure to associate the great toe malformation with heterotopic ossification led to a failure to diagnose FOP. She underwent repeated and unnecessary operative procedures to remove a recurrent lesion. FOP was finally suspected when the great toe malformation was correlated with the trauma-induced heterotopic ossification. Genetic analysis confirmed the presence of the classic FOP mutation (ACVR1 c.617G>A; R206H). This case highlights the importance of examining the great toes in anyone with heterotopic ossification. The association of malformations of the great toe with heterotopic ossification in all cases of classic FOP will lead to prompt clinical diagnosis and the prevention of iatrogenic harm.


Fibrodysplasia ossificans progressiva (FOP) Heterotopic ossification ACVR1 ALK2 


Conflicts of interest



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Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Mutlu Kartal-Kaess
    • 1
    • 6
    Email author
  • Eileen M. Shore
    • 2
  • Meiqi Xu
    • 2
  • Ludwig Schwering
    • 3
  • Markus Uhl
    • 4
  • Rudolf Korinthenberg
    • 1
  • Charlotte Niemeyer
    • 6
  • Frederick S. Kaplan
    • 5
  • Melchior Lauten
    • 7
  1. 1.Department of Pediatrics and Adolescent MedicineUniversity HospitalFreiburgGermany
  2. 2.Departments of Orthopaedic Surgery and GeneticsUniversity of Pennsylvania School of MedicinePhiladelphiaUSA
  3. 3.Departments of Orthopaedic Surgery and TraumatologyUniversity Hospital FreiburgFreiburgGermany
  4. 4.Department of RadiologySt. JosefskrankenhausFreiburgGermany
  5. 5.Departments of Orthopaedic Surgery and MedicineUniversity of Pennsylvania School of MedicinePhiladelphiaUSA
  6. 6.Department of Pediatric Hematology & OncologyUniversity HospitalFreiburgGermany
  7. 7.Department of Pediatric Hematology & OncologyUniversity Hospital Schleswig-Holstein, Campus LuebeckLuebeckGermany

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