Current studies have shown that the diagnosis of Klinefelter Syndrome does NOT indicate mental retardation, deviant behavior, or other generalizations. Most individuals diagnosed with this condition have average to superior intelligence with only about 20% scoring below average on standardized intelligence tests.

About 47XXY/Klinefelter Syndrome

47/XXY is estimated to occur in one out of 500 males, making it the most common sex chromosome variation.

Rather than the normal male chromosome pattern, 46XY, there is an extra X chromosome. The result is the 47/XXY arrangement. This variation happens when paired chromosomes fail to separate in the first or second stage of meiosis.

For many years, this condition has been called Klinefelter Syndrome, named for Dr. Harry Klinefelter, who published a paper in 1942 about nine men with enlarged breasts, sparse facial and body hair, small testes, and an inability to produce sperm. However, because the manifestations of 47XXY vary from person to person, some individuals may not have all of the characteristics described. Thus, medical researchers prefer the term XXY when describing this condition.

Causes

The exact cause of XXY is unknown. The extra chromosome can come from either parent.

How and when is XXY diagnosed?

Diagnosis can occur at any time in a person's life and many XXYs go undiagnosed for years. A blood sample will provide a karyotype or photograph of the individual's chromosomes to confirm diagnosis.

At present, diagnosis is likely to be made -

• prenatally, during amniocentesis,
• during childhood when developmental delays are present,
• at puberty when a boy's adolescent development is not proceeding in the typical way,
• during fertility studies, when a couple has been unsuccessful in conceiving a child, and
• in some instances, if continuing physical or psychological difficulties are present.

Health considerations for XXYs

XXYs have an increased risk for:

• autoimmune disorders, including type II diabetes and thyroiditis
• hypothyroidism
• breast cancer
• osteoporosis
• leg ulcers
• depression
• dental problems

Fertility Issues

Generally, XXYs are infertile, but a semen analysis is suggested to confirm this issue. Some 46XY/47XXY have preserved testicular function.

Recent advances in fertility treatment, such as testicular sperm extraction coupled with invitro fertili-zation and "intracytoplasmic sperm insertion" (ICSI) can result in a full term pregnancy without any chromosomal variations. Other options are donor insemination and adoption.

How does XXY Affect Children?

No one can predict for certain what effect the extra chromosome will have on an individual. Personalities are as varied in this group as in the general population. The spectrum of manifestations is wide. However, the following characteristics are said to occur more often in children with XXY. Keep in mind that a child may have only one symptom, while another may have more:

• delayed speech
• gross and fine motor delays
• sensory integration difficulties, including sensitivity to noise
• hypotonia or low muscle tone
• attention deficits
• auditory processing problems
• language-based learning disabilities, including reading difficulties
• social skill deficits
• anxiety
• self-esteem issues
• depression
• gynecomastia or swelling of breast tissue during puberty

XXY boys should be under the care of a pediatric endocrinologist who can initiate testosterone therapy in a timely manner.

The complete AAKSIS Introductory Brochure is also available for download: 151K Adobe Acrobat PDF document. The brochure may be printed out and distributed.