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Published on: February 3, 2012
Chromosomal variants in klinefelter syndrome
1Division for Human Genetics, Department for Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Austria.
Summary
Klinefelter syndrome (KS), the most common sex chromosome abnormality, presents diverse phenotypes based on karyotype. This review compares these variations to typical 47,XXY cases, highlighting differences in height and other features.
Area of Science:
- Genetics
- Endocrinology
- Reproductive Medicine
Background:
- Klinefelter syndrome (KS) is the most common human sex chromosome abnormality, affecting 1 in 600 males.
- Typical KS (47,XXY) involves tall stature, gynecomastia, small testes, infertility, and potential health issues like osteoporosis and diabetes.
- Diagnosis often occurs in adulthood due to infertility, as some features can be subtle.
Purpose of the Study:
- To review and compare phenotypes associated with various Klinefelter syndrome karyotypes.
- To contrast these diverse phenotypes with the established characteristics of the typical 47,XXY karyotype.
Main Methods:
- Categorization of patients into six groups based on specific karyotype variations.
- Review of literature to abstract and compare phenotypic presentations across these groups.
- Analysis of phenotypic differences, including height and specific clinical features.
Main Results:
- Patients with other numeric sex chromosome abnormalities showed increased height and developmental delay.
- Men with an additional isochromosome Xq experienced infertility and minor KS features but not increased height.
- Phenotypes for der(X), der(Y) rearrangements, and XXY females were not clearly distinguishable due to limited case numbers.
Conclusions:
- Karyotype variations in Klinefelter syndrome lead to a spectrum of phenotypes.
- The presence of SRY and X inactivation levels influence the phenotype in XX males.
- Further research is needed to define specific phenotypes for rarer karyotype variations.
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