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10 Cards in this Set
- Front
- Back
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The History of Klinefelters
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-Klinefelteret al. (1942) reported on 9 men with enlarged breasts, sparse facial and body hair, small testes, and inability to produce sperm
-In 1959, it was discovered that these men had an extra sex chromosome (XXY) |
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Introduction
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Klinefeltersyndrome AKA testicular dysgenesis
-Most common chromosomal disorder associated with male hypogonadismand infertility -Most males go through life without being diagnosed -Diagnosis, when made, usually occurs in adulthood due to hypogonadismand infertility |
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Is it inherited?
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This condition is not inherited, but usually occurs as a random event during the formation of reproductive cells (eggs and sperm). An error in cell division called nondisjunctioncan result in reproductive cells with an abnormal number of chromosomes.
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What is the pathophysiology
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-Phenotypic abnormalities, including mental retardation, directly related to number of extra X chromosomes
-Intelligence quotient (IQ) reduced by ~ 15 points for each extra X chromosome -49, XXXXY more severe than 48, XXXY -No racial predilection exists -Seen in males only |
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Major consequences of extra “X”
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-Small, firm testicles
-Small penis -Sparse pubic, axillae, and facial hair -Sexual problems -Gynecomastia -Tall stature -Abnormal body proportions -Long legs, short trunk |
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Frequency
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-Approximately 1 in 500 to 1,000 males born with extra sex chromosome in U.S.
-Over 3,000 affected males born yearly -Prevalence is 5 to 20 times higher in the mentally retarded than in general newborn population -About 40% of conceptiwith KF survive the fetal period |
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Fun Facts
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Most 47, XXY have normal intelligence
-Some may have behavioral and/or psychological problems –may be due to poor self-esteem -Mitralvalve prolapsein 55% of patients -Varicose veins occur in 20 to 40% of pts |
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What are the lab studies?
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-Cytogeneticstudies
-Hormone profile -High plasma FSH, LH, and estradiollevels -Low plasma testosterone levels -Low semen count -Echocardiography to detect mitralvalve prolapse |
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Treatment
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Should address three major facets of the disease
1. Hypogonadism, gynecomastia, and psychosocial problems 2. Testosterone replacement should begin at puberty 3. Plastic surgery for gynecomastia |
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Complications
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-Risk of breast carcinoma as high as 20 times that of healthy men
-Slight increase in acute leukemia, Hodgkin and non-Hodgkin lymphomas, CML, and gonadaltumors |
