Dorothy McGuire Williamson | McGuire Sister, 84

Dorothy McGuire Williamson, 84, who teamed with sisters Christine and Phyllis for a string of hits in the 50s and 60s as the popular McGuire Sisters singing group, died Friday at her son's home in Paradise Valley, Ariz., said her daughter-in-law, Karen Williamson. She had Parkinson's disease and age-related dementia.

The McGuire Sisters earned six gold records for hits, including 1954's "Sincerely" and 1957's "Sugartime." They were known for their sweet harmonies and identical outfits and hairdos.

They began singing together as children at their mother's Ohio church and then performed at weddings and church revivals. They got their big break in 1952 on Arthur Godfrey's Talent Scouts show, where they continued to perform for seven years.

The group made numerous appearances on television and toured into the late 1960s, making a last performance together on The Ed Sullivan Show in 1968. Ms. McGuire stepped back to raise her two sons, Williamson said. Christine also raised a family while Phyllis pursued a solo career, according to a 1986 profile in People Magazine, written after the trio had reunited and began doing nightclub and Las Vegas performances again.

The sister last performed together in the mid-2000s. Christine and Phyllis, 86 and 81, live in Las Vegas.

Ms. McGuire was married for 53 years to Lowell Williamson, a wealthy oilman. The couple had two sons, Rex and David. - AP