Double Y syndrome

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LD52.1 Male with double or multiple Y
A condition affecting males, caused by the presence of supernumerary Y chromosomes. This condition is asymptomatic. Confirmation is through observation of supernumerary Y chromosomes by karyotyping.


Double Y syndrome (Jacob's syndrome, 47 XYY syndrome, XYY syndrome) is a rare chromosomal disorder caused by the presence of an extra Y chromosome. Normally, males have 46 chromosomes including one X and one Y chromosome. Males with XYY syndrome have 47 chromosomes, two of which are Y chromosomes.

Characterized clinically by male tall stature evident from childhood, macrocephaly, facial features (mild hypertelorism, low set ears, a mildly flat malar region), speech delay and an increased risk for social and emotional difficulties, attention deficit hyperactive disorder and autistic spectrum disorder.

Genetic Links: genetic abnormalities | maternal age | Trisomy 21 | Trisomy 18 | Trisomy 13 | Trisomy X | trisomy mosaicism | Monosomy | Fragile X | Williams | Alagille | Philadelphia chromosome | mitochondria | VACTERL | hydatidiform mole | epigenetics | Prenatal Diagnosis | Neonatal Diagnosis | meiosis | mitosis | International Classification of Diseases | genetics

Some Recent Findings

  • Changes in the cohort composition of turner syndrome and severe non-diagnosis of Klinefelter, 47,XXX and 47,XYY syndrome: a nationwide cohort study[1] "Knowledge on the prevalence of sex chromosome abnormalities (SCAs) is limited, and delayed diagnosis or non-diagnosis of SCAs are a continuous concern. We aimed to investigate change over time in incidence, prevalence and age at diagnosis among Turner syndrome (TS), Klinefelter syndrome (KS), Triple X syndrome (Triple X) and Double Y syndrome (Double Y). This study is a nationwide cohort study in a public health care system. The Danish Cytogenetic Central Registry (DCCR) holds information on all karyotypes performed in Denmark since 1961. We identified all individuals in the DCCR with a relevant SCA during 1961-2014; TS: n = 1156; KS: n = 1235; Triple X: n = 197; and Double Y: n = 287. From Statistics Denmark, which holds an extensive collection of data on the Danish population, complete data concerning dates of death and migrations in and out of Denmark were retrieved for all individuals. The prevalence among newborns was as follows: TS: 59 per 100,000 females; KS: 57 per 100,000 males; Triple X: 11 per 100,000 females; and Double Y: 18 per 100,000 males. Compared with the expected number among newborns, all TS, 38% of KS, 13% of Triple X, and 18% of Double Y did eventually receive a diagnosis. The incidence of TS with other karyotypes than 45,X (P < 0.0001), KS (P = 0.02), and Double Y (P = 0.03) increased during the study period whereas the incidence of 45,X TS decreased (P = 0.0006). The incidence of Triple X was stable (P = 0.22). The prevalence of TS is higher than previously identified, and the karyotypic composition of the TS population is changing. Non-diagnosis is extensive among KS, Triple X and Double Y, whereas all TS seem to become diagnosed. The diagnostic activity has increased among TS with other karyotypes than 45,X as well as among KS and Double Y."
  • Auditory evoked response delays in children with 47,XYY syndrome[2] 47,XYY syndrome (XYY) is a male sex chromosome disorder where individuals have an X chromosome and two copies of the Y chromosome. XYY is associated with a physical phenotype and carries increased risk of neurodevelopmental disorders such as autism spectrum disorder (ASD). Latencies of auditory evoked responses measured by magnetoencephalography have shown atypical prolongations in several neuropsychiatric and genetic disorders; specifically, delayed auditory responses have been observed in ASD. In this study, we investigated the associations of genotype and clinical phenotype with auditory processing. Whole cortex magnetoencephalography recorded during a passive auditory paradigm (500 Hz tones) was used to assess the auditory evoked response in three groups of male children: idiopathic ASD, typically developing, and XYY boys. Response waveforms were computed for left and right auditory cortex and latencies of the ∼50 ms (M50) and ∼100 ms (M100) components were determined. M50 latencies were significantly delayed compared with typically developing controls in children with ASD in the right hemisphere only, and in children with XYY in the left hemisphere only, irrespective of whether they met diagnostic criteria for ASD. Findings on the later M100 component trended in the same directions but did not attain significance, due to increased variance. Replicating previous findings, decreased M50 and M100 latencies with age were observed bilaterally. Overall, while XYY shares an electrophysiological phenotype (delayed evoked response latency) with idiopathic ASD, the hemispheric differences warrant further investigation."
  • Selective advantage of euploid spermatocytes I in an azoospermic 47,XYY man with gonadal mosaicism[3] "Although most XYY men have normal sperm counts and are fertile (supposedly due to the loss of the extra Y before meiosis), there is a minority who are infertile. In these cases, the XYY spermatocytes are able to enter meiosis and form different synaptic configurations. With regard to mosaics, there is scarce well-defined information on the presence of the second Y and its meiotic behaviour. In this study, the chromosome constitution and the synaptic behaviour of pachytene spermatocytes from an azoospermic man with testicular hypotrophy and non-mosaic 47,XYY karyotype were analysed. Furthermore, we determined the chromosome constitution of the somatic Sertoli cells. Five karyotypically normal men with obstructive azoospermia, but having complete spermatogenesis, were included as controls. Immuno-FISH using specific protein markers of synapsis and recombination (SYCP3, SYCP1, BRCA1, MLH1, CREST) and a specific Yq12 DNA probe were used. In addition, we used the newly developed Super-Resolution Structured Illumination Microscopy (SR-SIM) to clearly define the synaptic configurations. FISH analysis was also performed on Sertoli cells. The histopathological analysis showed variable degrees of spermatogenesis development in the testicular tissue of the propositus. Immuno-FISH analysis showed that most of the primary spermatocytes were euploid 46, XY. The use of SR-SIM confirmed the existence of this euploidy. Only a few pachytene spermatocytes showed an aneuploid X + YY constitution. Sertoli cells showed two different populations with one or two Y chromosomes, in similar proportions. Thus an abnormal niche of sex-trisomic Sertoli cells should be also considered when searching for the origin of spermatogenesis failure in XYY men."
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Search term: Jacob's syndrome | XYY syndrome


  1. Berglund A, Viuff MH, Skakkebæk A, Chang S, Stochholm K & Gravholt CH. (2019). Changes in the cohort composition of turner syndrome and severe non-diagnosis of Klinefelter, 47,XXX and 47,XYY syndrome: a nationwide cohort study. Orphanet J Rare Dis , 14, 16. PMID: 30642344 DOI.
  2. Bloy L, Ku M, Edgar JC, Miller JS, Blaskey L, Ross J & Roberts TPL. (2019). Auditory evoked response delays in children with 47,XYY syndrome. Neuroreport , 30, 504-509. PMID: 30896674 DOI.
  3. Sciurano RB, Rahn IM, González Arias B, Rey Valzacchi G, Benavente R & Solari AJ. (2019). Selective advantage of euploid spermatocytes I in an azoospermic 47,XYY man with gonadal mosaicism. Hum. Reprod. , 34, 568-573. PMID: 30597018 DOI.


Kim IW, Khadilkar AC, Ko EY & Sabanegh ES. (2013). 47,XYY Syndrome and Male Infertility. Rev Urol , 15, 188-96. PMID: 24659916

Rives N, Siméon N, Milazzo JP, Barthélémy C & Macé B. (2003). Meiotic segregation of sex chromosomes in mosaic and non-mosaic XYY males: case reports and review of the literature. Int. J. Androl. , 26, 242-9. PMID: 12846800

Murakami J, Baba K, Minagawa N, Kono S, Yajima M & Iwamoto T. (1997). [A case of 47XYY syndrome presenting with male infertility]. Hinyokika Kiyo , 43, 433-6. PMID: 9250495

Oguma N, Shigeta C & Kamada N. (1996). XYY male and hematologic malignancy. Cancer Genet. Cytogenet. , 90, 179-81. PMID: 8830731


Rau RE, Carroll AJ, Heerema NA, Arland L, Carroll WL, Winick NJ, Raetz EA, Loh ML, Yang W, Relling MV, Dai Y, Devidas M & Hunger SP. (2017). Klinefelter syndrome and 47,XYY syndrome in children with B cell acute lymphoblastic leukaemia. Br. J. Haematol. , 179, 843-846. PMID: 27434379 DOI.

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Cite this page: Hill, M.A. (2024, April 19) Embryology Double Y syndrome. Retrieved from

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