At least one person was killed and six others, including a British software mogul, were missing on Monday after a sailing yacht carrying 22 people sank during a violent storm off the coast of Sicily, Italian officials said.

The yacht sank after a storm “with strong winds” struck around 5 a.m., according to Luciano Pischedda, the Italian Coast Guard official overseeing the rescue operations. The vessel had been anchored about a half-mile off Porticello, about 12 miles east of the Sicilian capital, Palermo.

Camper & Nicholsons, managers of the sailing yacht, said in an emailed statement that there were 12 guests and 10 crew onboard.

The authorities have yet to determine what caused the yacht to sink. “This will be ascertained later,” Mr. Pischedda said, adding that several crew members were in the hospital and had not spoken to investigators.

Among the dead and missing, four were British, two were American, and one was a man with dual citizenship from Canada and Antigua, he said.

One of those unaccounted for is Mike Lynch, a British software mogul who was acquitted in the United States in June of fraud, according to a person with knowledge of the matter who spoke on the condition of anonymity because they were not authorized to speak publicly about it.