XYY syndrome

XYY syndrome is a genetic condition in which a male has an extra Y chromosome. Symptoms are usually few. They may include being taller than average, acne, and an increased risk of learning problems. The person is generally otherwise normal, including normal fertility.Why do men commit crimes of violence? For some, the urge to violence may be inborn—traced to something called the Y chromosome...Once in every 500 male births, for example, the sex chromosome complement is XXY rather than XY, thus erring in the direction of femaleness. The resulting individual, called a Klinefelter male, is usually retarded, unusually tall and sterile.Erring in the other direction, however, is the XYY complement resulting in the 'supermale.' He is also unusually tall and somewhat retarded, but appears to be highly, perhaps too highly, sexually motivated...We were intrigued by Dr. Jacobs' contention that an extra Y chromosome results in tall stature, mild mental retardation, and severely disordered personality characterized by violent, aggressive behavior. We therefore planned to confirm and extend her studies.Syndrome Status for the XYYThe XXY male has long been thought to display a constellation of symptoms that makes him diagnosable; that is, he has achieved syndrome status. It would seem that the XYY male is fast achieving similar status. His symptoms, as we and other laboratories tend to think of them, are: extremely tall stature, long limbs and strikingly long arm span, facial acne, mild mental retardation, severe mental illness (including psychosis) and aggressive, antisocial behavior with a long history of arrests, frequently beginning at an early age.On reading newspaper accounts of Richard Speck, who murdered eight Chicago student nurses in 1966, we noted all these traits and therefore concluded that Speck was a likely candidate for the XYY disorder. Independently, a cytogenetic laboratory in Chicago confirmed this hunch, reinforcing our inclination to believe that the XYY syndrome is really coming of age. It seems quite possible that in the XYY male, exemplified by Speck, biologists are describing in genetic terms a certain type of defective criminal who has long been explicitly recognized by the forensic psychiatrist.Dr. Pergament said he and Dr. Sato, a research fellow, had absolutely no connection with the Speck case and never examined Speck. The report was also denied by Speck's attorney, Public Defender Gerald W. Getty. 'I never knew those doctors existed before I read about them in the paper,' Getty said. Getty did say that a chromosomal test was performed on Speck, before Speck's trial, by a geneticist from outside the Chicago area. He declined to identify the geneticist, and he said the results of the test never have been disclosed. 'It was agreed,' he said, 'that the results would not be disclosed unless I wished them disclosed. And I still don't.' In any case, Getty said, the results could not be used in an appeal—since they were not part of the trial evidence. If anything, he said, they could only be used in connection with a new trial.At the same time he made public reports from Vanderbilt University showing no abnormal makeup of Speck's chromosomes...Getty displayed a letter of Sept. 26, 1966, relating that photographic evidence of 18 cells from Speck's blood showed no chromosome abnormality. He also exhibited a letter of last July 3, indicating that 100 of 101 cells in a sample of Speck's blood studied after the original tests showed the normal 46 chromosomes. The other cell had 45, regarded by the Vanderbilt investigators as having no significance. XYY syndrome is a genetic condition in which a male has an extra Y chromosome. Symptoms are usually few. They may include being taller than average, acne, and an increased risk of learning problems. The person is generally otherwise normal, including normal fertility. The condition is generally not inherited from a person's parents but rather occurs as a result of a random event during sperm cell development. Diagnosis is by a chromosomal analysis. There are 47 chromosomes, instead of the usual 46, giving a 47,XYY karyotype. Treatment may include speech therapy or extra help with schoolwork. Outcomes are generally good. Prevention is not possible. The condition occurs in about 1 in 1,000 male births. Many people with the condition are unaware that they have it. The condition was first described in 1961. People with the 47,XYY karyotype have an increased growth rate from early childhood, with an average final height approximately 7 cm (3') above expected final height. In Edinburgh, Scotland, eight 47, XYY boys born 1967–1972 and identified in a newborn screening programme had an average height of 188.1 cm (6'2') at age 18—their fathers' average height was 174.1 cm (5'8½'), their mothers' average height was 162.8 cm (5'4'). The increased gene dosage of three X/Y chromosome pseudoautosomal region (PAR1) SHOX genes has been postulated as a cause of the increased stature seen in all three sex chromosome trisomies: 47,XXX, 47,XXY, and 47,XYY.Severe acne was noted in a very few early case reports, but dermatologists specializing in acne now doubt the existence of a relationship with 47,XYY. Prenatal testosterone levels are normal in 47,XYY males. Most 47,XYY males have normal sexual development and have normal fertility. In contrast to the other common sex chromosome aneuploidies—47,XXX and 47,XXY (Klinefelter syndrome)—the average IQ scores of 47,XYY boys identified by newborn screening programs were not reduced compared to the general population. In a summary of six prospective studies of 47,XYY boys identified by newborn screening programmes, twenty-eight 47,XYY boys had an average 100.76 verbal IQ, 108.79 performance IQ, and 105.00 full-scale IQ. In a systematic review including two prospective studies of 47,XYY boys identified by newborn screening programs and one retrospective study of 47,XYY men identified by screening men over 184 cm (6'½') in height, forty-two 47,XYY boys and men had an average 99.5 verbal IQ and 106.4 performance IQ. In prospective studies of 47,XYY boys identified by newborn screening programs, the IQ scores of 47,XYY boys were usually slightly lower than those of their siblings. In Edinburgh, fifteen 47,XYY boys with siblings identified in a newborn screening program had an average 104.0 verbal IQ and 106.7 performance IQ, while their siblings had an average 112.9 verbal IQ and 114.6 performance IQ. Approximately half of 47,XYY boys identified by newborn screening programs had learning difficulties—a higher proportion than found among siblings and above-average-IQ control groups. In Edinburgh, 54% of 47,XYY boys (7 of 13) identified in a newborn screening program received remedial reading teaching compared to 18% (4 of 22) in an above-average-IQ control group of 46,XY boys matched by their father's social class. In Boston, USA 55% of 47,XYY boys (6 of 11) identified in a newborn screening program had learning difficulties and received part-time resource room help compared to 11% (1 of 9) in an above-average-IQ control group of 46,XY boys with familial balanced autosomal chromosome translocations. Developmental delays and behavioral problems are also possible, but these characteristics vary widely among affected boys and men, are not unique to 47,XYY and are managed no differently from in 46,XY males. Aggression is not seen more frequently in 47,XYY males.