The natural history of fibrodysplasia ossificans progressiva: A prospective, global 36-month study

• Published in: Genetics in medicine Vol. 24; no. 12; pp. 2422 - 2433
• Main Authors: Pignolo, Robert J., Baujat, Geneviève, Brown, Matthew A., De Cunto, Carmen, Hsiao, Edward C., Keen, Richard, Al Mukaddam, Mona, Le Quan Sang, Kim-Hanh, Wilson, Amy, Marino, Rose, Strahs, Andrew, Kaplan, Frederick S.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.12.2022
• Subjects: Adolescent; Adult; Child; Child, Preschool; Female; Fibrodysplasia ossificans progressiva; Humans; Male; Middle Aged; Myositis Ossificans - diagnostic imaging; Myositis Ossificans - epidemiology; Natural history study; Ossification, Heterotopic - diagnostic imaging; Ossification, Heterotopic - genetics; Pain; Prospective Studies; Young Adult; Fibrodysplasia ossificans progressiva; Natural history study
• ISSN: 1098-3600; 1530-0366
• DOI: 10.1016/j.gim.2022.08.013

We report the first prospective, international, natural history study of the ultra-rare genetic disorder fibrodysplasia ossificans progressiva (FOP). FOP is characterized by painful, recurrent flare-ups, and disabling, cumulative heterotopic ossification (HO) in soft tissues. Individuals aged ≤65 years with classical FOP (ACVR1R206H variant) were assessed at baseline and over 36 months. In total, 114 individuals participated; 33 completed the study (mean follow up: 26.8 months). Median age was 15.0 (range: 4-56) years; 54.4% were male. During the study, 82 (71.9%) individuals reported 229 flare-ups (upper back: 17.9%, hip: 14.8%, shoulder: 10.9%). After 84 days, 14 of 52 (26.9%) imaged flare-ups had new HO at the flare-up site (mean new HO volume: 28.8 × 103 mm3). Mean baseline low-dose whole-body computed tomography (excluding head) HO volume was 314.4 × 103 mm3; lowest at 2 to <8 years (68.8 × 103 mm3) and increasing by age (25-65 years: 575.2 × 103 mm3). The mean annualized volume of new HO was 23.6 × 103 mm3/year; highest at 8 to <15 and 15 to <25 years (21.9 × 103 and 41.5 × 103 mm3/year, respectively) and lowest at 25 to 65 years (4.6 × 103 mm3/year). Results from individuals receiving standard care for up to 3 years in this natural history study show the debilitating effect and progressive nature of FOP cross-sectionally and longitudinally, with greatest progression during childhood and early adulthood. [Display omitted]