Teriparatide treatment in a young man with idiopatic Juvenile Osteoporosis Diagnosis

PARISI MS; BAGUR A; OLIVERI B

Montreal

Congreso; 30th Meeting ASBMR; 2008

ASBMR

Idiopathic Juvenile Osteoporosis (IJO) diagnosis is based on the exclusion of other diseases causing severe demineralization and fractures in childhood.A 27y old man, diagnosed with IJO, was treated with Teriparatide 18m. He was healthy until 14y old, when knees and ankle pain developed, and suffered femoral and humerus fractures. On presentation (18y) he uses crutches because of lumbar, knees, and ankle pain. Rx: compression fractures of all vertebral bodies, genu varum, and aseptic necrosis of right femoral neck. L2L4BMD (DXA) Z-score was -7.3. Bone scan was unspecific with multiple areas of hypercaptation. Lab tests were normal, except for high bone alkaline phosphatase (BALP). Bone biopsy showed osteoporosis features, histomorphometry evidenced reduced osteobalst (Ob) and erosion surfaces, and negative double label tetracicline (TC).He received calcium (Ca) and vit D 12m, and bisphosphonates for 2 y, that were suspended when he suffered a humeral fracture, and bone biopsy showed an increase in osteoid surface, still reduced bone volume and osteoblast surface, and without double label TC. However, bone pain diminished and BMD increased. Thereafter he continued on Ca/vit D 5y. Teriparatide (20ug/d), vit D2 (800UI/d), and Ca (0.5g/d) treatment was indicated based on the evidence of reduced Ob activity. The patient signed an informed consent approved by the Hospital Ethical Committee. Follow up: serum Ca, phosphate, BALP, iPTH, 25OHD, cross laps (CTX), osteocalcin (BGP), creatinine, uric acid, hemogram, hepatogram; and urinary Ca and creatinine at 0, 1, and every 3m. BMD and Rx every 6m; and bone biopsy and bone scan at 0, and 18m.At baseline bone volume, osteoid surface, and osteoid thickness where in the normal range, with a low % single label TC; Ob surface persisted reduced. With Teriparatide, bone pain disappeared. Lab tests were normal, except for BALP (table 1). L2L4 BMD increased 19.9%, from 0.592 to 0.710g/cm2. Bone scan areas of hypercaptation disappeared. Bone biopsy results are pending. A caryotype informed a Robertsonian translocation (13.14). Molecular studies in progress.Teriparatide produced clinical, densitometric and centellographic improvement. The response to treatment could sustain the hypothesis of an Ob defect. The abnormal caryotype suggests the possibility of an existing gene mutation.