This condition was first identified by Dr. Harry Klinefelter at the Massachusetts General Hospital in Boston.  A report published he and his coworkers reported case studies on nine men who had enlarged breasts, sparse facial and body hair and an inability to produce sperm.

 

Now more appropriately referred to as XXY Male of XXY Male Syndrome, males born with this condition have an extra sex chromosome XXY instead of the usual  genotype XY.  It is associated with a 47XXY karyotype and statistically occurs in 1/500 newborns.

Clinical features

 Klinefelter is occasionally associated with lymphatic blockage or fetal hydrops and thus is included in a discussion of developmental disorders of the lymphatics.

Original symptoms included tall stature, long upper extremities, poor pubertal development, microorchidism, enlarged breasts, sparce facial and body hair, small testes and subsequent sterility.

Recent studies have expanded the original symptoms to include infertility, incomplete masculinization; feminine, or pear shaped, body and body hair distribution, decreased libido,  osteoporosis,  taurodontism, venous disease (which may include mitral valve prolapse, varicose veins and venous ulcers),  learning and emotional disorders, autoimmune disorders,  low energy and self esteem,  communication difficulties, especially with expressive language, frustration-based outbursts, motor skills issue and developmental delays.  Also, there is a 20 times increased risk for XXY males to develop breast cancer than non XXY males.

Treatment

For proper care and treatment early diagnosis is important. The treatment includes hormone therapy such as testosterone replacement. Other treatment aspects should include the psychosocial and emotional problems, needed treatment for physiological side affects and later on even genetic counseling.

FOR FURTHER INFORMATION AND RESOURCES:

Klinefelter Syndrome

Author: Harold Chen, MD, MS, FAAP, FACMG, Chief, Professor, Department of Pediatrics, Section of Perinatal Genetics, Louisiana State University Medical Center

http://www.emedicine.com/PED/topic1252.htm

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Klinefelter Syndrome?

Or is he XXY? There IS a difference!

A Parent’s View

http://xxy.50megs.com/

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Understanding Klinefelter Syndrome

http://www.nichd.nih.gov/publications/pubs/klinefelter.htm

A Guide for XXY Males and Their Families

Written by:
Robert Bock
Office of Research Reporting, NICHD

NIH Pub. No. 93-3202
August 1993

CONTENTS

What is Klinefelter Syndrome?
Chromosomes and Klinefelter Syndrome
Causes
Diagnosis
What to Tell Families, Friends, and XXY boys
Childhood
Detecting Language Problems Early
Guidelines for Detecting Language Problems
The XXY Boy in the Classroom
Help Under the Law
Teaching Tips
Adolescence
Testosterone Treatment
Chromosomal Variations
Sexuality
Infertility
Health Considerations
Adulthood
Resources

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Klinefelter’s Syndrome

Med Line Plus

http://www.nlm.nih.gov/medlineplus/klinefelterssyndrome.html br /

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XXY Information KLINEFELTER SYNDROME

http://47xxy.org/XXYframe.html

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Klinefelter Organization

http://www.klinefelter.org.uk/

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KLINEFELTER’S SYNDROME ASSOCIATION UK

http://www.ksa-uk.co.uk/Index.html

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ADDITIONAL RESOURCES

 

Klinefelter Syndrome & Associates, Inc.

PO Box 119

Roseville, CA 95678-0119

Phone: 916.773.1449

Fax: 916.773.1449

E-mail: help@genetic.org

Web site: http://www.genetic.org/ks/ (Japenese version)

[Note: group name may change to X & Y Family Genetic Network and include XXX, and XXY and the multiple sex chromosome variants]

 

- Resources for families

- Introductory video about XXY, by mother whose son has Klinefelter Syndrome

- The Even Exchange, Newsletter

American Association for Klinefelter Syndrome Information and Support (AAKSIS)

Klinefelter Syndrome Support Group Home Page, numerous links to other organizations and resources, created by an adult with Klinefelter Syndrome, regional groups, varients, international groups

International Groups:

Australia

Australian Klinefelter Support Group

4 Victoria Rd

Acquire Fields NEW 02564 AUSTRALIA

02-605-2837

Victoria Support Group

41 Jesmond Rd
Cordon, Victoria 03136 AUSTRALIA
03-9723-6148

Klinefelter Syndrome Support Group

P.O.Box 3
Glendenning Mail Center NEW 2761 AUSTRALIA
02-9628-4142

Canada

Canada Klinefelter Support Group

Apt. 3, 2867 Young St.
Toronto, ON. Canada M4N 2J5
416. 481.3171

England (United Kingdom)

Klinefelter’s Syndrome Association

56 Little Yeldham Road

Little Yeldham, Halstead, Essex CO9 4QT

Klinefelter Organisation [formerly the Klinefelter's Syndrome Club UK (KSCUK)]

Belgium

Belgische vereniging voor het syndroom van Klinefelter

Sweden and Denmark

Swedish Klinefelter Association (Svenska XXY& Klinefelterföreningen)

Klinefelter Syndrome Booklets, Danish version or English version, The Turner Center

Norwegian Klinefelter Site

Other information:

Chromosomal Problems Discovered through Prenatal Diagnosis: Klinefelter Syndrome, (.pdf) PacNorGG spanish version

Diagnosis and Treatment of Klinefelter Syndrome, CM SMYTH, University of Washington, Hospital Practice, 1999

Guide for XXY Males and Their Families, R Bock, National Institute of Child Health & Human Development (NICHD), National Institutes of Health (NIH)

Klinefelter Syndrome (47,XXY), English & Spanish (.pdf files), Pacific Northwest Regional Genetics Group (PacNoRGG)

Klinefelter Syndrome (XXY): A Parent’s View

Klinefelter Syndrome, eMedicine

Klinefelter Syndrome, Ohio Support Network

Misleading information in early Klinefelter studies

Human Growth Foundation

Teaching tips for males with XXY

The Turner Center Center for Information,Counseling, and Research on chromosome anomalies (includes Klinefelter Syndrome: An Orientation and Klinefelter Syndrome: Brief Information)

Understanding Klinefelter Syndrome: A Guide for XXY Males and their Families, R Boca, INCHED, NIHAU Pub. No. 93-3202, August 1993

XXY List Members

What is XXY? Hambley, (french version) XYY individual’s sites