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XYY syndrome

    '''XYY syndrome''' is a aneuploidy of the sex chromosomes in which a human male receives an extra XY sex-determination system|Y chromosome in each cell (biology)|cell hence having a karyotype of '''47XYY''' XYY syndrome is also called '''XYY-trisomy''' '''47XYY aneuploidy''' or '''Supermale syndrome'''

    First case

    The first published report of a man with a 47XYY chromosome constitution was by Dr. Avery A. Sandberg et al. of Buffalo New York in 1961 It was an incidental finding in a normal 44-year-old 6 ft. cm tall man of average intelligence


    Physical traits

    XYY syndrome typically causes no unusual physical features or medical problems Males with this syndrome may be slightly taller than average and are typically a few inches taller than their father and siblings
    Skeletal malformations may also accompany XYY syndrome at a higher rate than in the general population Severe facial acne has occasionally been reported but dermatologists specializing in acne (Plewig & Kligman 2000) now doubt the existence of a relationship with XYY Several other physical characteristics including large hands and feet have been associated (although not definitively) with XYY syndrome Any physical characteristics however are usually so slight that they are insufficient evidence to suggest a diagnosis
    Most males with XYY syndrome have normal sexual development and are able to conceive children
    Since there are no distinct physical characteristics the condition usually is only detected during genetic analysis for other reasons

    Behavioral characteristics

    XYY boys have an increased risk of minor speech and motor skill delays and learning disabilities with roughly half requiring some special education intervention Behavior problems are common but are not unique to XYY boys and managed no differently than XY boys

    Cause and prevalence

    XYY syndrome is not inherited but usually occurs as a random event during the formation of sperm cells An error in cell division called nondisjunction can result in sperm cells with an extra copy of the Y chromosome If one of these atypical reproductive cells contributes to the genetic makeup of a child the child will have an extra Y chromosome in each of the body's cells In some cases the addition of an extra Y chromosome occurs as an accident during cell division in early fetal development
    The incidence of this condition is approximately one in 850 males


    • Public domain text from NLM Genetics Home Reference: 47XYY syndrome
    • Sandberg A. A.; Koepf G. F.; Ishihara T.; Hauschka T. S. (August 26, 1961) "An XYY human male" Lancet 2 488-9
    • Milunsky Jeff M. (2004) Prenatal Diagnosis of Sex Chromosome Abnormalities In Milunsky Aubrey (Ed) House Genetic Disorders and the Fetus : Diagnosis Prevention and Treatment (5th ed) pp. 297-340 Baltimore: The Johns Hopkins University Press ISBN 0801879280
    • Allanson Judith E.; Graham Gail E. (2002) Sex chromosome abnormalities In Rimoin David L.; Connor J. Michael; Pyeritz Reed E.; Korf Bruce R. (Eds) Emery and Rimoin's Principles and Practice of Medical Genetics (4th ed) pp. 1184-1201 : Churchill-Livingstone ISBN 0443064342
    • Plewig Gerd; Kligman Albert M. (2000) Acne and Rosacea (3rd ed) : Springer-Verlag ISBN 3540667512