Generalized arterial calcification of infancy: treatment with bisphosphonates

Background: A baby girl developed respiratory distress immediately after birth and required supplemental oxygen. She was born at term via lower-segment cesarean section. The parents were nonconsanguineous, and antenatal ultrasonography during the pregnancy at 18 and 32 weeks of gestation did not reveal any abnormalities. On examination at birth, no pulses were palpable; however, the baby's blood pressure was normal and no remarkable abnormalities were detected. Ultrasonography revealed widespread arterial calcification.

Investigations: Chest and abdominal radiography at birth and serial abdominal, renal and cardiac ultrasonography at follow-up examinations; dual-energy X-ray absorptiometry during treatment with bisphosphonates; genetic screening.

Diagnosis: Generalized arterial calcification of infancy, secondary to compound, heterozygous mutations in the ENPP1 gene, pL661V and pE668K of the paternal chromosome, and pN792S in the maternal chromosome.

Management: Low-dose disodium pamidronate (0.1 mg/kg per week for 4 weeks), which commenced on the seventh day after birth and was changed to oral risedronate sodium (1 mg/kg per week as a single dose) at 4 weeks of age. Complete resolution of arterial calcification was seen by 3 months of age. At 12 months, ergocalciferol was added at a dose of 5,000 U daily for 6 weeks, followed by 200 U daily owing to the patient's vitamin D deficiency and elevated parathyroid hormone level. Treatment with bisphosphonates is ongoing, but is planned to be discontinued at 3 years of age. The child has remained healthy and developmentally normal.