Jordan Feldstein, a well-known manager of music acts and brother of actor Jonah Hill, died last December. (Photo: Jordan Feldstein)

Jonah Hill’s brother Jordan Feldstein, well-known in the music industry as Maroon 5’s manager, died last December from an condition that usually affects people in old age, according to a coroner’s report. Yet, he was just 40.

Feldstein died as a result of a deep vein thrombosis in his leg, according to a report by the Los Angeles County Coroner’s Office.

Deep vein thrombosis occurs when a blood clot (i.e. thrombus) forms in one or more of the deep veins, usually the legs. The usual symptoms are leg pain or swelling, but they also can occur with no symptoms, according to the Mayo Clinic.

The principal causes are a blood condition affecting clotting or by inactivity for long periods of time, such as after surgery or an accident.

The condition becomes serious when the blood clot breaks loose and travels through the body and lodges in the lungs, blocking blood flow to the heart and other organs.

The official cause of death was a “pulmonary thromboembolism,” resulting from a clot from another part of his body, according to the Coroner’s Office.

Feldstein also suffered from acute bronchopneumonia and obesity, the report stated.

At the time, the family said Jordan had called 911 to complain about shortness of breath. He was in full cardiac arrest by the time paramedics arrived.

Feldstein founded Career Artist Management, which managed music acts.

He managed Maroon 5 for 15 years and was said to be instrumental in getting his childhood friend Adam Levine a chair on ABC’s “The Voice.”

His company also managed Miguel, The B-52s, Elle King and Rick Springfield.