Further Outpatient Care

Management of Klinefelter syndrome includes the following:

Endocrinologist - To assist in management and treatment with testosterone replacement therapy
Speech therapy
Occupational and physical therapy
Behavioral consultation
Regular exercise and upper body strengthening

The Association for X and Y Chromosome Variations (AXYS) is an outreach and outpatient group that serves individuals and their families affected by X and Y chromosome aneuploidies, such as Klinefelter syndrome and its variants. Their web address is www.axysgenetic.org.

Further Inpatient Care

Admission for supportive care is not necessary in patients with Klinefelter syndrome.

Inpatient & Outpatient Medications

Administer regular testosterone injections.

Complications

Patients with Klinefelter syndrome have an increased risk of extratesticular germ cell tumors and possibly increased risk of breast cancer.^[64]The risk of breast carcinoma in 47,XXY men may approach 20 times that of 46,XY men. The cause may be related to the estradiol:testosterone ratio being several fold higher in 47,XXY men than in karyotypically normal men or is possibly due to an increased peripheral conversion of testosterone to estradiol in men with Klinefelter syndrome.^[65] Other neoplasias, occurring in 1.6% of patients, include acute leukemia, Hodgkin and non-Hodgkin lymphomas, chronic myelogenous leukemia, and other myeloproliferative diseases. Gonadal and extragonadal germ cell tumors (mediastinal germ cell tumors, teratoma, teratocarcinoma, choriocarcinoma) may also occur.

Psychological and psychiatric complications may occur in 47,XXY men with lower-than-average intelligence, hypogonadism, or impotence. The results of one study found that patients with Klinefelter syndrome are at elevated risk for psychopathologies such as autism and schizotypal traits, with schizotypal traits increasing with age. Deficiencies in verbal abilities are associated with increased autism traits, whereas deficiencies in visuospatial abilities are more strongly associated with increased schizotypal traits.^[66]

Decreased bone density occurs in 25% of men with Klinefelter syndrome, possibly reflecting the impact of reduced bone formation, increased bone resorption, and/or hypogonadism. Vertebral collapse may result from osteoporosis.^[67]

All patients with Klinefelter syndrome should be informed about the increased risk of deep vein thrombosis and should have their hematocrit levels monitored to avoid increased viscosity.^[68]

Associated endocrine complications include diabetes mellitus, hypothyroidism, empty sella syndrome, hypoparathyroidism, and precocious puberty in association with human chorionic gonadotropin (hCG)–producing germ cell tumors. A study reported that prepubertal boys (aged 4-12 years) with Klinefelter syndrome are at elevated risk for truncal obesity, insulin resistance, and childhood metabolic syndrome. Reduced physical activity is associated with these risk factors.^[69]

Autoimmune diseases, including systemic lupus erythematosus, Sjögren syndrome, and rheumatoid arthritis, are more common, with frequencies similar to those found in 46,XX females.

Benign prostatic hyperplasia may result from testosterone supplementation. Adults undergoing such therapy should be screened for prostatic enlargement starting at age 30 years.

In males with polysomic X Klinefelter syndrome, the mortality rate due to cerebrovascular diseases such as aortic valvular disease and berry aneurysm rupture is more than 6 times that in healthy males aged 25-84 years. Enhanced platelet aggregation, thrombotic disease, and hypercoagulability have been demonstrated and may be related to increased estrogen levels. Development of varicose veins and leg ulcers may result from venous stasis.^[68]

Prognosis

Early studies of men with XXY Klinefelter syndrome produced disturbing findings of an increased risk of psychiatric disturbance, criminality, and mental retardation. These results are considered highly questionable because of selection bias from institutionalized populations.

Babies with the XXY form differ little from healthy children. The results of one cohort study on nonmosaic XXY infants younger than 2 years found that most reported XXY neonates had normal external genitalia and height and weight within the normal range and were not dysmorphic. Indications for postnatal karyotyping included delayed ambulation and speech skills. These findings, along with previously reported clinical and biological features, suggest that early detection of Klinefelter syndrome is vital in monitoring potential developmental problems.^[70]

Although boys with the 47,XXY karyotype may struggle through adolescence with limited academic success, many frustrations, and, in a few instances, serious emotional or behavioral difficulties, most move toward full independence from their families as they enter adulthood. Some have completed graduate education and have a normal level of functioning.

The findings of a study including 87 Australian men with Klinefelter syndrome suggest that adults diagnosed with this disease later in life experience similar personal and psychosocial difficulties compared with those diagnosed at younger ages. These individuals would benefit from early detection and intervention.^[71]

Life span is presumably normal.

Hypogonadism, low libido, and psychosocial problems can be helped by testosterone treatment.

Gynecomastia can be corrected by mastectomy.

Patient Education

Useful resources for patients and families include the following:

Association for X and Y Chromosome Variations
PO Box 861
Mendenhall, PA 19357
Phone: 888-999-9428
American Speech-Language-Hearing Association
2200 Research Boulevard
Rockville, MD 20850
Phone: 800-498-2071

Questions

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Media Gallery

Adolescent male with gynecomastia and Klinefelter syndrome.
Child with Klinefelter syndrome. Other than a thin build and disproportionately long arms and legs, the phenotype is normal.
G-banded 47,XXY karyotype.
Adolescent male with Klinefelter syndrome who has female-type distribution of pubic hair and testicular dysgenesis.