Morbidity, mortality, and socioeconomics in Klinefelter syndrome and 47,XYY syndrome: a comparative review

Abstract

Context: Klinefelter syndrome (KS, 47,XXY) and 47,XYY syndrome are genetic conditions characterized by a supernumerary sex chromosome. The conditions share many traits, but considerable phenotypic differences are seen between the two. Focusing on morbidity, mortality, and socioeconomics, this review highli ghts similarities and differences. Methods: Relevant literature was identified through PubMed with the follo wing search terms; 'Klinefelter', '47,XXY', '47,XYY', and 'Jacobs syndrome'. Included journal articles were chosen at the authors’ discretion. Results: KS and 47,XYY are the most common sex chromosome disorders in m ales, with an expected prevalence of 152 and 98 per 100,000 newborn males, respectively. Non-diagnosis is extensive, as only about 38% of KS and 18% of 47,XYY are diagnosed. Both conditions are associated with an increased mortality risk and increased risk of a variety of diseases and other health-related problems affecting virtuall y every organ system. Early diagnosis seems to predict a lesser comorbidity burden. N eurocognitive deficits as well as social and behavioral problems are commonly described. Both syndromes are associated with poor socioeconomic for example, lower income an d educational level and higher rates of crime. Infertility is a hallmark of KS, but fertility seems also reduced in 47,XYY. Conclusion: Being born as a boy with an extra X or Y chromosome is associat ed with increased mortality and excess morbidity, partially expressed in a sex chromosome-specific pattern. Both syndromes continue to be greatly underdia gnosed, even though early intervention may improve the overall outcome. Earlier diagnosis to initiate timely counseling and treatment should be emphasized.

Keywords

• klinefelter syndrome
• jacobs syndrome
• 47
• xyy
• morbidity
• mortality