In one of his final appearances, on Jerry Seinfeld’s “Comedians in Cars Getting Coffee” (via The Atlantic), Garry Shandling revealed that he’d been diagnosed with a rare and poorly understood disorder: hyperparathyroidism. Per Mayo Clinic, hyperparathyroidism affects the parathyroid hormones in the neck responsible for generating a hormone that help maintain adequate levels of calcium in the bloodstream. In hyperparathyroidism, too much of the hormone is produced, leading calcium to be leeched from bone tissue and appear in excess quantities in the blood. The condition can lead to kidney stones, osteoporosis, and heart disease.

Symptoms of hyperparathyroidism include forgetfulness, fatigue, excessive urination, and joint pain. Shandling joked to Seinfeld that the disorder’s impact on his life was minimal: “The symptoms are so much like being an older Jewish man, no one noticed!” But left untreated (often by surgery), the condition can increase the risk of cancer, dementia, and heart attacks.