Ottavio Missoni, a onetime Olympic athlete who became the patriarch of a fashion brand known for its zigzag-patterned knitwear, died May 9 just months after his eldest son disappeared without a trace. He was 92.

The Missoni company issued a statement saying that Mr. Missoni died at his home in the northern Italian town of Sumirago, where the business is based.

In January, Mr. Missoni’s eldest child and the company’s chief executive, 58-year-old Vittorio Missoni, disappeared with his wife and four others while flying in a small plane during a vacation to a Venezuelan island. They have not been found, and the cause of the disappearance remains a mystery.

Known to friends by his nickname, “Tai,” Ottavio Missoni founded the company in 1953, along with his wife, Rosita Jelmini, who survives him. They went on to create a fashion dynasty, with the couple’s three children and their offspring involved in the business.

“It was Tai and Rosita who founded, along with few others, Italian fashion in the 1950s,” said Mario Boselli, chairman of the Italian Fashion Chamber, who knew Mr. Missoni for decades. “We are speaking of a historical era, the start of ready-to-wear in Italy, that defined the success of ‘Made in Italy.’ ”

Ottavio Missoni and Margherita Missoni attend Missoni Loves Leaves cocktail party during the Milan Design Week on April 16, 2012 in Milan, Italy. (Pier Marco Tacca/Getty Images)

Laura Biagiotti, who was among those early designers, said Missoni patterns “became almost a second flag for Italy.”

Born on Feb. 11, 1921, in what is now Dubrovnik, Croatia, Mr. Missoni was fond of saying he came into the fashion business “by accident.”

His wife’s family owned a textile factory and produced shawls, and the newlyweds started their own business in 1953 with a shop producing knitwear near Milan.

At the beginning, they produced athletic wear, likely inspired by Mr. Missoni himself, who had been a track-and-field star specializing in 400-meter relays and hurdles. He won several national medals and competed in the 1948 Olympics, finishing sixth in the 400-meter hurdles.

In World War II, he was taken prisoner during the battle of El Alamein and held for four years by the British.

The Missoni brand got its first break in 1958, when the Rinascente department store commissioned 500 colorful vertically striped shirt dresses — the first to carry the Missoni label.

The Missoni brand gained quick popularity with its original striped and zigzag patterns.

The Missonis, who often wore their own creations in everyday life, first showed their collection in Milan in 1966. Their first boutique in the United States opened in 1970, and by the end of the decade Missoni knitwear had been dubbed “the new status symbol of Italian design.”

The brand’s appeal in the United States has hardly cooled. In 2011, demand was so high for a Missoni limited-edition line for Target that the retailer’s Web site crashed.

Missoni creations have been exhibited at New York’s Metropolitan Museum of Art and Whitney Museum.

The fashion house also has designed costumes for a production of “Lucia di Lammermoor” at La Scala, starring Luciano Pavarotti and Luciana Serra.

Mr. Missoni and his wife turned the business over to their children in 1997. Ottavio and Rosita’s granddaughter, Margherita, has gained recognition as a model promoting Missoni perfume.

— Associated Press