Questions and Answers
What genetic abnormality is most commonly associated with Klinefelter syndrome?
Which of the following is NOT a commonly observed physical characteristic in individuals with Klinefelter syndrome?
How does the severity of clinical manifestations in Klinefelter syndrome relate to the number of additional X chromosomes?
What year was Klinefelter syndrome first reported by Dr. Harry Klinefelter?
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Which hormone levels are typically unsuppressed in Klinefelter syndrome, contributing to its symptoms?
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What is the primary developmental area potentially affected by Klinefelter syndrome?
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What is the prevalence of Klinefelter syndrome in males with mental retardation compared to the general population?
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What is one of the implications of testosterone deficiency in Klinefelter syndrome?
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Which of the following is a common clinical sign of Klinefelter syndrome?
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What is the annual incidence of males born with Klinefelter syndrome in the United States?
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What is the primary significance of Klinefelter syndrome (KS)?
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What percentage of Klinefelter syndrome cases are attributed to maternal non-disjunction?
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Which of the following cancers are Klinefelter syndrome patients at increased risk for?
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Which autoimmune disorder is NOT mentioned as being at high risk for Klinefelter syndrome patients?
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What condition is suggested to result from higher-than-normal estrogen/testosterone ratios in Klinefelter syndrome?
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What is the estimated percentage of Klinefelter syndrome patients at risk for diabetes mellitus?
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Infertility in Klinefelter syndrome patients is primarily caused by which of the following?
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What chronic condition is listed as a significant complication of Klinefelter syndrome?
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During which stage of meiosis does maternal non-disjunction most commonly occur in relation to Klinefelter syndrome?
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Which hormone is suggested to provide protection against autoimmunity in Klinefelter syndrome patients?
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What is NOT a benefit of testosterone replacement therapy according to the information provided?
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Which method of testosterone administration is typically preferred for treating hypogonadism?
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What is the typical adult dose of intramuscular testosterone enanthate or cypionate?
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What is a reported side effect of oral androgen preparations like methyltestosterone?
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What age group is typically administered 50 mg of intramuscular testosterone monthly?
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Which testosterone delivery method is known to cause minimal skin irritation but may leave a sticky residue?
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What is a common expected outcome of starting testosterone replacement therapy during puberty?
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What is one drawback of using oral testosterone preparations over parenteral methods?
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Which administration route for testosterone may require more frequent patch changes to avoid irritation?
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Which condition does NOT benefit from testosterone treatment?
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Study Notes
Definitions
- Klinefelter syndrome (KS) is characterized by phenotypic and functional abnormalities due to one or more extra X chromosomes in males.
- Clinical features arise from testosterone deficiency and unsuppressed hormone secretion from the pituitary gland.
- Developmental delays in physical, language, and social aspects are common in KS.
- Common physical manifestations include tall stature, small testes (male hypogonadism), gynecomastia (breast development), and low sperm count (azoospermia).
- Severity of symptoms increases with the number of extra X chromosomes.
- Named after Dr. Harry Klinefelter, who reported the initial cases in 1942; XXY genotype was identified in 1959.
Prevalence
- Classic KS, with a karyotype of 47,XXY, occurs in approximately 1 in every 500–1,000 male births.
- About 80–90% of KS cases have the 47,XXY genotype.
- Over 3,000 males born annually in the U.S. are affected by this condition.
- No racial predilection exists for KS.
- Prevalence is significantly higher (5–20 times) in individuals with mental retardation compared to the general population.
- Miscarriage rates for embryos with KS are high; only 40% survive to full term.
- Recurrence rate for KS is similar to that in the general population.
Significance
- KS is significant due to its association with chronic illnesses and various clinical manifestations.
- Increased risk for chronic conditions includes diabetes mellitus, systemic lupus erythematosus (SLE), and rheumatoid arthritis (RA).
- Patients face a heightened risk for specific cancers, notably testicular and breast cancer.
- Maternal non-disjunction accounts for slightly over half of KS cases, primarily during the first meiotic division.
- Paternal non-disjunction also contributes to cases of KS.
- Low serum testosterone levels contribute to autoimmune disorder risks, with potential serological effects of estrogen.
Complications
- Serious complications include diabetes mellitus (8% prevalence), SLE, RA, testicular and breast cancer, and osteoporosis.
- Depression is a noted side effect for individuals with KS.
- Despite complications, individuals often lead a normal lifespan.
Treatment and Management
- Testosterone replacement therapy should ideally start at puberty to address sexual dysfunction and muscular issues.
- Benefits of testosterone treatment include improved mood, self-image, physical endurance, and a decrease in language problems.
- Administration routes for testosterone therapy include parenteral, oral, transdermal, and topical methods.
- Recommended treatment begins with 200 mg intramuscularly every three weeks for adults; 50 mg monthly for ages 11-12, with adjustments based on response.
- Oral androgens like methyltestosterone are less effective and may pose risks for hyperbilirubinemia.
- Transdermal options include skin patches (Testoderm II and Androderm), each with unique application and skin irritation profiles.
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Description
Explore the characteristics, prevalence, and impact of Klinefelter syndrome (KS) in males. This quiz delves into the clinical features, common physical manifestations, and statistical insights surrounding KS. Test your knowledge on this genetic condition and its effects on development.
