It started with a 10-month-old boy, who I’ll call Jake, who was feeding poorly. Between 6 and 10 months, a time when infants should be growing rapidly, he hadn’t gained a pound. His diapers were constantly wet – he was urinating at a high rate. He was irritable and fussy.
When a lab test found an extremely elevated blood calcium level, Jake was sent to the emergency room. Such an extreme elevation posed a risk of compromising his heart and kidney function. His blood pressure was sky-high. “He needed immediate IV fluid to bring his calcium down, and an immediate workup,” says Andrew Dauber, then a first-year fellow in endocrinology.
Jake was admitted to Children’s and Dauber took part in the consult with his mentor Joel Hirschhorn, a pediatric endocrinologist trained in genetics. “His kidneys were so calcified they were turning into stones,” Dauber recalls. The senior nephrologist on the team said Jake had the most severe case of nephrocalcinosis he’d seen.
The team put Jake on low-calcium formula and his calcium level slowly came down. His diagnosis was idiopathic infantile hypercalcemia — meaning they had no idea what was causing Jake’s calcium levels to be so high. …