P292 Heterotopic bone formation not related to POH/FOP disease: a

P292
Heterotopic bone formation not related to POH/FOP disease: a new entity?
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E.F. Belligni , E. Biamino , E. Di Gregorio , A. Calcia , C. De Filippi , G.B. Ferrero , A. Brusco , M. Tartaglia , M. Silengo
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S.C.d.U. Genetica Medica, Città della Salute e della Scienza, Torino, Italy
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Dipartimento di Genetica, Biologia e Biochimica, University of Torino
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Dipartimento di Ematologia, Oncologia e Medicina Molecolare, Istituto Superiore di Sanità, Rome,Italy
We present a unique case of congenital multiple and massive periarticular calcifications in a 3 years old female, with normal
cognitive function. She is the first child of italian non consanguineous parents, born at term after an uneventuful pregnancy
and delivery. Progressive diffuse joints limitation was noticed since first month of life. Skeletal survey and CT scan at 8
months showed severe shoulder’s, elbow’s, wrist’s, hip’s, knee’s and ankle’s joints limitation due to impressive periarticular calcifications. The posterior longitudinal ligament was completely ossified. At 10 months, total body MRI highlighted
intercostal and masticatory muscles calcification. Her posture was forced in flexion of elbows, knees and ankles, and movements of the head were completely abolished. She had brachydactyly and camptodactyly of hands and feet. Her eyes
were deep-set, the philtrum short and smooth, but no other striking dysmorphisms were present.
Neurocognitive milestones were properly achieved.
Extensive metabolic workup gave normal results: serum and urine calcium levels were normal, as well as serum and urine
phosphorum, sodium, potassium, magnesium, creatinine, PTH, 1-25-OH-Vit D, 25-OH-VitD levels.
Molecular analysis of ACVR1 and GNAS genes ruled out both Fibrodysplasia Ossificans Progressiva (FOP) and Progressive Osseous Heteroplasia (POH), two distinct severely disabling heritable disorders of connective tissue characterized by
progressive heterotopic ossification.
CGH array analysis (Agilent platform, 70 K) identified a de novo 2p14 duplication (820 Kb), neither described before in the
literature, nor reported as a benign CNV in the Database of Genomic Variants. Exome sequencing is pending.