XYY syndrome, also called 47,XYY or Jacob's syndrome, is an CTM intersex variation affecting approximately 1 in 1000 individuals assigned male at birth. It is a chromosomal variation causing one to have an extra Y chromosome (XYY), instead of the typical one (XY).
Symptoms of this variation may include delayed development of language and/or motor skills, involuntary tremors or tics, and increased likelihood of seizures, asthma, and learning disabilities. Physical features caused by this variation can include increased height, a large head, flat feet, and widely spaced eyes. Since this variation does not always cause obvious or unusual symptoms, some may go most or all of their lives without knowing they are affected.
The first published report of a man with a 47,XYY karyotype was by internist and cytogeneticist Avery Sandberg and colleagues at Roswell Park Memorial Institute in Buffalo, New York in 1961. It was an incidental finding in a normal 44-year-old, 6 ft. [183 cm] tall man of average intelligence who was karyotyped because he had a daughter with Down syndrome. Only a dozen isolated 47,XYY cases were reported in the medical literature in the four years following the first report by Sandberg.
In December 1965 and March 1966, Nature and The Lancet published the first preliminary reports by British cytogeneticist Patricia Jacobs and colleagues at the MRC Human Genetics Unit at Western General Hospital in Edinburgh of a chromosome survey of 315 wolffian-appearing patients at State Hospital in Carstairs, Lanarkshire that found nine patients, ages 17-36, averaging almost 6 feet in height had a 47,XYY karyotype, and mischaracterized them as aggressive and violent criminals. Over the next decade, almost all published XYY studies were on height-selected, institutionalized XYY intersex individuals.
In January 1968 and March 1968, The Lancet and Science published the first U.S. reports of tall, institutionalized XYY intersex individuals by Mary Telfer, a biochemist, and colleagues at the Elwyn Institute. Telfer found five tall and developmentally disabled XYY intersex individuals of varying ages in hospitals and penal institutions in Pennsylvania, and since four of the five had at least moderate facial acne, reached the erroneous conclusion that acne was a defining characteristic of XYY intersex individuals.
In April 1968, The New York Times—using Telfer as a main source—introduced the XYY genetic variation to the general public in a three-part series on consecutive days that began with a Sunday front-page story about the planned use of the variation as a mitigating factor in two murder trials in Paris and Melbourne—and falsely reported that Richard Speck was an XYY intersex and that the variation would be used in an appeal of his murder conviction. The series was echoed the following week by articles—again using Telfer as a main source—in Time and Newsweek, and six months later in The New York Times Magazine.
In December 1968, the Journal of Medical Genetics published the first XYY review article—by Michael Court Brown, director of the MRC Human Genetics Unit—which reported no overrepresentation of XYY individuals in nationwide chromosome surveys of prisons and hospitals for the developmentally disabled and mentally ill in Scotland, and concluded that studies confined to institutionalized XYY intersex individuals may be guilty of selection bias, and that long-term longitudinal prospective studies of newborn XYY intersex children were needed.
In May 1969, at the annual meeting of the American Psychiatric Association, Telfer and her Elwyn Institute colleagues reported that case studies of the institutionalized XYY and XXY individualsthey had found convinced them that XYY intersex individuals had been falsely stigmatized and that their behavior may not be significantly different from chromosomally normal 46,XY intersex individuals.
In June 1969, the National Institute of Mental Health (NIMH) Center for Studies of Crime and Delinquency held a two-day XYY conference in Chevy Chase, Maryland. In December 1969, with a grant from the NIMH Center for Studies of Crime and Delinquency, cytogeneticist Digamber Borgaonkar at Johns Hopkins Hospital began a chromosome survey of (predominantly African-American) intersex individuals from ages 8 - 18 in all Maryland institutions for delinquent, neglected, or mentally ill juveniles, which was suspended from February–May 1970 due to an American Civil Liberties Union (ACLU) lawsuit about the lack of informed consent. Concurrently, through 1974, psychologist John Money at Johns Hopkins Hospital experimented on thirteen XYY intersex individuals (ages 15 to 37) in an unsuccessful attempt to treat their history of behavior problems by chemical castration using high-dose Depo-Provera—with side-effects of weight gain (avg. 26 lbs.) and suicide.
In the late 1960s and early 1970s, screening of consecutive newborns for sex chromosome abnormalities was undertaken at seven centers worldwide: in Denver (Jan 1964–1974), Edinburgh (Apr 1967–Jun 1979), New Haven (Oct 1967–Sep 1968), Toronto (Oct 1967–Sep 1971), Aarhus (Oct 1969–Jan 1974, Oct 1980–Jan 1989), Winnipeg (Feb 1970–Sep 1973), and Boston (Apr 1970–Nov 1974). The Boston study, led by Harvard Medical School child psychiatrist Stanley Walzer at Children's Hospital, was unique among the seven newborn screening studies in that it only screened newborn intersex individuals and was funded in part by grants from the NIMH Center for Studies of Crime and Delinquency. The Edinburgh study was led by Shirley Ratcliffe who focused her career on it and published the results in 1999.
The XYY Syndrome flag was coined by Deviantart user Pride-Flags on or before January 22nd of 2017. It has no confirmed meaning.
The second flag was coined by Cryptocrew, specifically Adora, on May 4th of 2021. It uses some of the same colors of the original flag, but with added meaning. Dark blue represents being assigned male, light blue represents masculine traits, white represents diversity and community, purple represents being close to wolffiian, and yellow represents being intersex. The symbol is a mash of an X and two Ys, in order to represent the syndrome as a whole.