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Birth Defects Risk Factor Series 47, XYY


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47,XYY was first reported in 1961. 47,XYY is a sex chromosomal abnormality that typically involves the presence of an extra Y chromosome. Mosaicism may occur where some cells in the body have 47,XYY and other cells in the body have a different chromosome complement, with the most common total karyotype being 47,XYY/46,XY. Of total cases with 47,XYY, 80-90% are 47,XYY and 10-20% are 47,XYY/46,XY (Nielsen and Wohlert, 1991; Jacobs et al., 1974). Etiology 47,XYY is always of paternal origin and results from nondisjunction in the second meiotic division or post zygotic mitosis (Jacobs and Hassold, 1995). Fertilization of an X egg by a YY sperm would result in a conceptus with 47,XYY. Mosaic 47,XYY/46,XY results from mitotic nondisjunction after fertilization. Phenotype The clinical features of 47,XYY are subtle and can be variable. Individuals with 47,XYY are usually physically normal as infants (Buyse, 1990; Jacobs et al., 1974). Postnatal diagnosis is unlikely to be made in the first decade of life, and many individuals with 47,XYY may not be diagnosed at all (Abramsky and Chapple, 1997; Nielsen and Videbec, 1984). Individuals with 47,XYY tend to be tall and thin (Linden et al, 1996; Buyse, 1990). They are usually fertile (Linden et al, 1996). Individuals with 47,XYY are not at increased risk of mental retardation, although they may have speech delay, hyperactivity, and educational difficulties (Linden et al, 1996; Buyse, 1990). Behavioral problems are not more common in 47,XYY individuals (Buyse, 1990). Generally, individuals with prenatally diagnosed 47,XYY have fewer developmental problems than individuals with postnatally diagnosed 47,XYY (Linden and Bender, 2002).


Individuals with 47,XYY may have hypospadias, small testicles, and undescended testicles (Buyse, 1990), and there may be an association with renal agenesis and renal cystic dysplasia (Rudnik-Schoneborn et al., 1996).


Prenatal diagnosis


47,XYY may be prenatally diagnosed through cytogenetic analysis of cells obtained through such procedures as amniocentesis and chorionic villus sampling.


Fetal sex chromosomal abnormalities (47,XXX, 47,XXY, and 47,XYY) have been associated with increased nuchal translucency but normal maternal serum levels of free beta-human chorionic gonadotropin (hCG) and pregnancy-assisted plasma protein-A (PAPP-A) in the first trimester (Spencer et al., 2000; Sebire et al., 1998). However, first-trimester nuchal translucency and maternal serum screening are not routinely done in the United States. One investigation found that the proportion of 47,XYY cases in a population at increased risk of Down syndrome as a result of maternal serum screening was not greater than expected for the general population (Ryall et al., 2001). Moreover, fetuses with 47,XYY typically do not have an abnormal ultrasound.


Thus cases of 47,XYY syndrome will most likely be diagnosed prenatally incidental to a cytogenetic analysis for other reasons such as advanced maternal age (Abramsky and Chapple, 1997).







The prevalence of 47,XYY has been reported to be 9.89.3/10,000 male births or 5.02.0/10,000 births (Table 1). One study reported the rate of 47,XYY among amniocentesis tests to be 2.2/10,000 (Horger et al., 2001).




47,XYY does not result in increased likelihood of fetal death over that of fetuses with normal chromosomes (Ferguson-Smith and Yates, 1984; Hassold and Jacobs, 1984). In one investigation, 3.6% of 47,XYY cases that were not electively terminated were fetal deaths (Hook et al, 1989).


Some 47,XYY fetuses will be electively terminated when identified prenatally (Table 2). Elective termination rates have varied by study. Differences in termination rates among studies may reflect differences in time periods of the studies or differences in access to and/or use of prenatal diagnosis and elective termination. Termination rates for 47,XYY/46,XY are lower than for 47,XYY (Meschede et al., 1998).




Individuals with 47,XYY are believed to have a normal life span (Buyse, 1990). One investigation reported that the infant mortality rate associated with all sex chromosome abnormalities increased during 1985997 (Lee et al., 2001).


Birth weight


The birth weight of infants with 47,XYY does not differ from that of controls (Ratcliffe et al., 1990; Robinson et al., 1979).


Table 1. Prevalence per 10,000 births of 47,XYY
Reference Location Time period Rate
Nielsen and Wohlert, 1991 Denmark 1969988 6.0, 11.8*
Hansteen et al., 1982 Norway 1978979 5.5
Buckton et al., 1980 Scotland 1976977 10.0, 19.3*
Hamerton et al., 1975 Canada 1970972 5.0, 9.8*
Jacobs et al., 1974 Scotland 1967972 12.0, 17.8*
Friedrich and Nielsen, 1973 Denmark 1969971 5.9, 11.5*
*rate per male births only


Table 2. Termination rates (%) of prenatally diagnosed 47,XYY cases
Reference termination rate (%)
Horger et al., 2001 0
Sagi et al, 2001 75
Christian et al, 2000 20
Perrotin et al, 2000 50
Meschede et al, 1998 10
Verp et al, 1988 50
Verp et al, 1988 (review) 57
Holmes-Siedle et al, 1987 33
Holmes-Siedle et al, 1987 (review) 50
Nielsen and Videbec, 1984 100






By definition, 47,XYY occurs exclusively among males. However, individuals with 47,XYY and female phenotype have been reported (Benasayag et al., 2001).


Parental age:


Risk of 47,XYY is not associated with increasing maternal age (Ferguson-Smith and Yates, 1984; Hassold and Jacobs, 1984; Hook, 1981). This observation is consistent with the paternal origin of the condition.




47,XYY rates are similar in white and Japanese populations but may be lower in blacks (Buyse, 1990).




Although one investigation reported a higher rate of sex chromosomal abnormalities with maternal gestational diabetes, the rate of 47,XYY was not increased (Moore et al., 2002).


Assisted Reproductive Technology (ART)


47,XYY has been reported among infants conceived by intracytoplasmic sperm injection (ICSI) (Aboulghar et al., 2001).


  • Aboulghar H, Aboulghar M, Mansour R, Serour G, Amin Y, Al-Inany H. A prospective controlled study of karyotyping for 430 consecutive babies conceived through intracytoplasmic sperm injection. Fertil Steril 2001;76:249-253.
  • Abramsky L, Chapple J. 47,XXY (Klinefelter syndrome) and 47,XYY: Estimated rates of and indication for postnatal diagnosis with implications for prenatal counselling. Prenat Diagn 1997;17:363-368.
  • Autio-Harmainen H, Rapola J, Aula P. Fetal gonadal histology in XXXXY, XYY and XXX syndromes. Clin Genet 1980;18:1-5.
  • Benasayag S, Rittler M, Nieto F, Torres de Aguirre N, Reyes M, Copelli S. 47,XYY karyotype and normal SRY in a patient with a female phenotype. J Pediatr Endocrinol Metab 2001;14:797-801.
  • Buckton KE, O'Riordan ML, Ratcliffe S, Slight J, Mitchell M, McBeath S, Keay AJ, Barr D, Short M. A G-band study of chromosomes in liveborn infants. Ann Hum Genet 1980;43:227-239.
  • Buyse ME, ed. Chromosome X, Chromosome XYY. In: Birth Defects Encyclopedia. Cambridge, Massachusetts: Blackwell Scientific Publications, 1990:400-401.
  • Christian SM, Koehn D, Pillay R, MacDougall A, Wilson RD. Parental decisions following prenatal diagnosis of sex chromosome aneuploidy: a trend over time. Prenat Diagn 2000;20:37-40.
  • Ferguson-Smith MA, Yates JR. Maternal age specific rates for chromosome aberrations and factors influencing them: report of a collaborative European study on 52 965 amniocenteses. Prenat Diagn 1984;4:5-44.
  • Friedrich U, Nielsen J. Chromosome studies in 5,049 consecutive newborn children. Clin Genet 1973;4:333-343.
  • Hamerton JL, Canning N, Ray M, Smith S. A cytogenetic survey of 14,069 newborn infants. I. Incidence of chromosome abnormalities. Clin Genet 1975;8:223-243.
  • Hansteen IL, Varslot K, Steen-Johnsen J, Langard S. Cytogenetic screening of a newborn population. Clin Genet 1982;21:309-314.
  • Hansteen IL, Varslot K, Steen-Johnsen J, Langard S. Cytogenetic screening of a newborn population. Clin Genet 1982;21:309-314.
  • Hassold TJ, Jacobs PA. Trisomy in man. Annu Rev Genet 1984;18:69-97.
  • Holmes-Siedle M, Ryynanen M, Lindenbaum RH. Parental decisions regarding termination of pregnancy following prenatal detection of sex chromosome abnormality. Prenat Diagn 1987;7:239-244.
  • Hook EB. Rates of chromosome abnormalities at different maternal ages. Obstet Gynecol 1981;58:282-285.
  • Hook EB, Topol BB, Cross PK. The natural history of cytogenetically abnormal fetuses detected at midtrimester amniocentesis which are not terminated electively: new data and estimates of the excess and relative risk of late fetal death associated with 47,+21 and some other abnormal karyotypes. Am J Hum Genet 1989;45:855-861.
  • Horger EO, Finch H, Vincent VA. A single physician's experience with four thousand six hundred genetic amniocenteses. Am J Obstet Gynecol 2001;185:279-288.
  • Jacobs PA, Hassold TJ. The origin of numerical chromosome abnormalities. Adv Genet 1995;33:10133.
  • Jacobs PA, Melville M, Ratcliffe S, Keay AJ, Syme J. A cytogenetic survey of 11,680 newborn infants. Ann Hum Genet 1974;37:359-376.
  • Lee K, Khoshnood B, Chen L, Wall SN, Cromie WJ, Mittendorf RL. Infant mortality from congenital malformations in the United States, 1970997. Obstet Gynecol 2001;98:620-627.
  • Linden MG, Bender BG, Robinson A. Intrauterine diagnosis of sex chromosome aneuploidy. Obstet Gynecol 1996;87:468-475.
  • Linden MG, Bender BG. Fifty-one prenatally diagnosed children and adolescents with sex chromosome abnormalities. Am J Med Genet 2002;110:118.
  • Meschede D, Louwen F, Nippert I, Holzgreve W, Miny P, Horst J. Low rates of pregnancy termination for prenatally diagnosed Klinefelter syndrome and other sex chromosome polysomies. Am J Med Genet 1998;80:330-334.
  • Moore LL, Bradlee ML, Singer MR, Rothman KJ, Milunsky A. Chromosomal anomalies among the offspring of women with gestational diabetes. Am J Epidemiol. 2002;155:719-724.
  • Nielsen J, Videbech P. Diagnosing of chromosome abnormalities in Denmark. Clin Genet 1984;26:422-428.
  • Nielsen J, Wohlert M. Chromosome abnormalities found among 34,910 newborn children: results from a 13-year incidence study in Arhus, Denmark. Hum Genet 1991;87:81-83.
  • Perrotin F, Guichet A, Marret H, Potin J, Body G, Lansac J. Devenir prenatal des anomalies des chromosomes sexuels diagnostiquees pendant la grossesse. Analyse reptrospective de 47 cas. J Gynecol Obstet Biol Reprod (Paris) 2000;29:668-676.
  • Ratcliffe SG, Butler GE, Jones M. Edinburgh study of growth and development of children with sex chromosome abnormalities. IV. Birth Defects Orig Artic Ser 1990;26:1-44.
  • Robinson A, Bender BG, Linden MG, Salbenblatt JA. Sex chromosome aneuploidy: the Denver Prospective Study. Birth Defects Orig Artic Ser 1990;26:5915.
  • Rudnik-Schoneborn S, Schuler HM, Schwanitz G, Hansmann M, Zerres K. Further arguments for non-fortuitous association of Potter sequence with XYY males. Ann Genet 1996;39:43-46.
  • Ryall RG, Callen D, Cocciolone R, Duvnjak A, Esca R, Frantzis N, Gjerde EM, Haan EA, Hocking T, Sutherland G, Thomas DW, Webb F. Karyotypes found in the population declared at increased risk of Down syndrome following maternal serum screening. Prenat Diagn 2001;21:553-557.
  • Sagi M, Meiner V, Reshef N, Dagan J, Zlotogora J. Prenatal diagnosis of sex chromosome aneuploidy: possible reasons for high rates of pregnancy termination. Prenat Diagn 2001;21:461-465.
  • Sebire NJ, Snijders RJ, Brown R, Southall T, Nicolaides KH. Detection of sex chromosome abnormalities by nuchal translucency screening at 104 weeks. Prenat Diagn 1998;18:581-584.
  • Spencer K, Tul N, Nicolaides KH.. Maternal serum free beta-hCG and PAPP-A in fetal sex chromosome defects in the first trimester. Prenat Diagn 2000;20:390-394.

Please Note: The primary purpose of this report is to provide background necessary for conducting cluster investigations. It summarizes literature about risk factors associated with this defect. The strengths and limitations of each reference were not critically examined prior to inclusion in this report. Consumers and professionals using this information are advised to consult the references given for more in-depth information. 

This report is for information purposes only and is not intended to diagnose, cure, mitigate, treat, or prevent disease or other conditions and is not intended to provide a determination or assessment of the state of health. Individuals affected by this condition should consult their physician and when appropriate, seek genetic counseling.

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Birth Defects Epidemiology and Surveillance
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Document E58-10957F                    Revised August 2002

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Last updated February 10, 2012