EARLY BISPHOSPHONATE TREATMENT IN AN INFANT WITH COL1A1 OSTEOGENESIS IMPERFECTA

Abstract

INTRODUCITON/BACKGROUND
Bisphosphonate therapy is the mainstay treatment of patients with OI. It helps to increase bone mass, decrease fracture rate, improve growth and muscle strength as well as improve mobility. Initial studies were performed among older children and adolescents; however, recently, early treatment in infants with moderate-to-severe OI has been shown to be safe. The optimal age of starting is controversial, especially less than 6 months as there is a need to balance the benefits of therapy with the safety of treatment.

CASE
We report an 11-month-old male whose prenatal scan revealed suspicion of skeletal dysplasia. Parents are nonconsanguineous and with no family history of frequent fractures or genetic disorders. He was born term via EMLSCS for intrauterine growth restriction with highly resistant Doppler. The birth history was uneventful. He has low-set ears, macrocephalic with widened anterior fontanelle, triangular facies, and grey sclera, his hips were in a flexed and abducted position with bowed bilateral lower limbs. The child had bilateral thigh swelling with deformity at birth. Radiological evaluation showed a bilateral femur fracture. He sustained a bilateral humerus fracture at day 12 of life, a left radius fracture at 2 months old and a right humerus fracture at 3 months old. Whole Exome Sequencing test revealed a pathogenic variant of COL1A1 gene. The child was started on pamidronate at the age of 5 months old with a dose of 0.1mg/kg then the dose was increased to 0.25 mg/kg, and was given 3 consecutive days, monthly then every 2 months. The pamidronate dose was further increased to 0.5 mg/kg for 3 days, given 3 monthly. He tolerated treatment well and no adverse effects were noted. He has had no new fractures since treatment started.

CONCLUSION
OI is a complex disorder and involves multidisciplinary management. Early and appropriate treatment could help increase bone density and prevent recurrent fractures.