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KLINEFELTER (XXY) SYNDROME

Background
Medical Management Considerations
References
Resources for Families
Advisory Committee
Publication Information

Learning Points

  • Restate that Klinefelter (XXY) Syndrome is one of the most common single causes of hypogonadism and infertility in males (occurrence is 1:1,000 to 1:500, males only).
  • Recognize that Klinefelter (XXY) Syndrome should be considered in all boys with mental retardation as well as those with psychosocial, learning, or school adjustment difficulties.
  • Upon diagnosis, delineate medical management considerations; e.g.,
    • Perform complete physical and neurological exam to detect congenital anomalies
    • Perform chromosome analysis (karyotype) to confirm diagnosis
    • Provide genetic counseling, including discussion of recurrence risk
    • Discuss possibility of SSI enrollment
  • Recommend hormone replacement therapy (HRT) for individuals with Klinefelter (XXY) Syndrome by age 11 to 13; refer to qualified endocrinologist for depotestosterone injections, patches, or oral medication.
  • Restate possible side effects of testosterone replacement therapy; e.g.
    • Minor allergic reaction at injection site
    • Increased aggressive behavior
    • Benign prostatic hyperplasia (usually only occurs after age 40)
  • Refer families to appropriate resources on Klinefelter (XXY) Syndrome.

BACKGROUND
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Description and Cause

Klinefelter Syndrome is one of the most common single causes of hypogonadism and infertility in males. It is the result of an extra sex chromosome (denoted 47,XXY), which can have physical, developmental, and learning implications. Not all males with an extra sex chromosome develop Klinefelter Syndrome; of those who do, most are able to lead healthy, normal lives. Variants of the syndrome include 48,XXYY; 48,XXXY; 49,XXXXY; and XY/XXY mosaic. In these variants, the classic features of Klinefelter Syndrome may be exaggerated.

Occurrence

  • 1:1,000 to 1:500 (males only)

Characteristic Features

  • Sterility (95%+)
  • Decreased testosterone levels
  • Increased excretion of gonadotropin
  • Hypogonadism
  • Gynecomastia (pubertal breast development)
  • Diminished secondary sexual characteristics
  • Hand tremors
  • Tall, slim stature
  • Behavioral problems (outbursts of frustration; immaturity; poor judgment)
  • Learning disabilities
  • Difficulty concentrating
  • Delays in language development
  • Delayed emotional development
  • Social difficulties; shyness
  • Sleep disturbances
  • Decreased energy, endurance, and agility
  • Psychological problems; low self-esteem
  • Decreased sexual drive

Possible Associations

  • Speech and language difficulties
  • Autoimmune disorders (diabetes type I, thyroiditis, lupus erythematosus)
  • Chronic bronchitis
  • Breast cancer (increased risk associated with Klinefelter Syndrome)
  • Radioulnar synostosis
  • Hypospadias
  • Cryptorchidism
  • Osteoporosis

MEDICAL MANAGEMENT CONSIDERATIONS
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Note: These considerations are in addition to the normal medical care provided to an individual without Klinefelter Syndrome. All recommendations can be addressed through clinical examination by the primary care provider, unless otherwise noted.

Upon Diagnosis

Klinefelter Syndrome should be considered in all boys with mental retardation as well as those with psychosocial, learning, or school adjustment difficulties. Klinefelter Syndrome may not be suspected until the child begins school or reaches puberty. The following should be performed as soon as diagnosis is suspected:

  • Perform complete physical and neurological exam to detect congenital anomalies
  • Perform chromosome analysis (karyotype) to confirm diagnosis
  • Refer for psychiatric evaluation as needed
  • Refer to speech pathologist for speech and language therapy evaluation as needed
  • Provide genetic counseling, including discussion of recurrence risk
  • Discuss possibility of SSI enrollment

Childhood (1 to 13 years)

  • Recommend hormone replacement therapy (HRT) by age 11 to 13; refer to qualified endocrinologist for depotestosterone injections, patches, or oral medication
  • Advise patient and family that HRT can help most characteristic features but not sterility
  • Monitor speech and language progress
  • Monitor for signs of precocious puberty
  • Refer for speech and language therapy evaluation
  • Monitor school progress
  • Emphasize importance of educational techniques like visual learning; individual attention; and organized structure
  • Recommend and arrange for dental care
  • Refer to early intervention programs and Klinefelter Syndrome/disability support groups as needed

Possible Side Effects of Testosterone Treatment

  • Minor allergic reaction at injection site
  • Increased aggressive behavior
  • Benign prostatic hyperplasia (usually only occurs after age 40)

Adolescence and Adulthood (13 years and over)

  • Consider mastectomy for gynecomastia
  • Recommend and teach regular self examination for breast cancer
  • Monitor blood hormone levels annually
  • Continue hormone replacement therapy
  • Screen regularly for benign prostatic hyperplasia
  • Reassure patients that they are capable of completely normal sexual function (erection, ejaculation, etc.)
  • Provide counseling regarding adoption and infertility
  • Monitor prevocational training and vocational activities

REFERENCES
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Peer-reviewed Journal Articles/Academies

Bock, R. (1993). Understanding Klinefelter Syndrome: A Guide for XXY Males and Their Families. National Institutes of Health, Office of Research Reporting. Pub. No. 93-3202 (August).

Bradshaw, K. (1997). Contrasexual Disorders and Delayed Puberty. Hospital Medicine, 33(10), 51- 57.

Giodano, S.H., Buzdar, A.U., Hortobagyi, G.N. (2002). Breast Cancer in Men [Review]. Annals of Internal Medicine, 137(8), 678-87.

Graham, J. et al. (1988). Oral and Written Language Abilities of XXY Boys: Implications for Anticipatory Guidance. Pediatrics, 81(6).

Klinefelter’s Syndrome. (1988). Lancet, 1(8598), 1316-1317.

Kurkrock, E.A., Tunuguntla, H.S., Busby, J.E., Gandour-Edwards, R., Goldman, L.A. (2002). Klinefelter’s Syndrome and Precocious Puberty: A Harbinger for Tumor. Urology, 60(3), 514.

Mandoki, M.W, et al. (1991). A Review of Klinefelter’s Syndrome in Children and Adolescents. Journal of the American Academy of Child and Adolescent Psychiatry, 30(2), 167-172.

Manning, M.A., Hoyme, H.E., (2002). Diagnosis and Management of the Adolescent Boy with Klinefelter Syndrome [Review]. Adolescent Medicine, 13(2), 367-74, viii.

Money, J. (1993). Specific Neurocognitional Impairments Associated with Turner (45,X) and Klinefelter (47,XXY) Syndromes: A Review. Social Biology, 40(1-2), 147-151.

Smyth, C.M.,William, J.B. (1998). Klinefelter Syndrome. Archives of Internal Medicine, 158(12), 1309-1314.

Tatum, W.O. IV, et al. (1998). Seizures in Klinefelter’s Syndrome. Pediatric Neurology, 19(4), 275-278.

Visootsak, J., Aylstock, M., Graham, J.M. (2001). Klinefelter Syndrome and its Variants: An Update and Review for the Primary Pediatrician [Review]. Clinical Pediatrics, 40(12), 639-51.

Special Interest Groups/Other Publications

Capute, Arnold J. and Pasquale J. Accardo. 1996. Developmental Disabilities in Infancy and Childhood vol. I: Neurodevelopmental Diagnosis and Treatment. Baltimore: Paul H. Brookes Publishing Co., Inc.

Capute, Arnold J. and Pasquale J. Accardo. 1996. Developmental Disabilities in Infancy and Childhood vol II: The Spectrum of Developmental Disabilities. Baltimore: Paul H. Brookes Publishing Co., Inc.

Klinefelter Syndrome and Associates. 1999. “About XXY: Information About Klinefelter Syndrome.” Accessed March 10, 1999. *Link no longer working as of 5/31/07.

RESOURCES FOR FAMILIES
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Alliance of Genetic Support Groups
301-336-GENE

American Speech, Language and Hearing Association
800-638-TALK

California Department of Developmental Services
916-654-1690

California Regional Centers
915-654-1958

Exceptional Parent Magazine
800-247-8080

Klinefelter Syndrome & Associates
916-773-2999

Klinefelter Syndrome Association
414-987-5782

Klinefelter Syndrome Support Group
888-718-9309

March of Dimes Birth Defects Foundation
914-428-7100

National Institute of Mental Health, Child Psychiatry Branch
301-435-4513

ADVISORY COMMITTEE
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Theodore A. Kastner, M.D., M.S.
Felice Weber Parisi, M.D., M.P.H.
Patrick J. Maher, M.D.
Patricia Samuelson, M.D.
Larry Yin, M.D., M.S.P.H., F.A.A.P.

PUBLICATION INFORMATION
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This document does not provide advice regarding medical diagnosis or treatment for any individual case, and any opinions or statements contained in this document are not intended to serve as a standard of medical care. Physicians are encouraged to view the considerations presented in this document in light of evolving scientific information. This document is not intended for use by the layperson. Reproduction of this document may be done with proper credit given to California Department of Developmental Services.