Klinefelter Syndrome: What should we tell prospective parents?

Area of Science:

• Genetics
• Reproductive Medicine
• Pediatrics

Background:

• Klinefelter syndrome (47,XXY) is the most common sex chromosome aneuploidy (SCA), occurring in 1 in 600 male pregnancies.
• Historically, ascertainment bias limited understanding of KS phenotypes, with only 25% diagnosed due to clinical issues across the lifespan.
• Increased identification of KS is noted with the rise of antenatal noninvasive prenatal testing (NIPT).

Purpose of the Study:

• To highlight the critical need for population-based longitudinal data for individuals with KS identified antenatally.
• To address the challenges in providing balanced genetic counseling for KS due to data limitations.
• To improve understanding and management of KS across the life course.

Main Methods:

• This study reviews existing literature and highlights data gaps.
• It discusses the impact of ascertainment bias on the known KS phenotype.
• It examines the implications of increased NIPT identification on KS diagnosis and management.

Main Results:

• A significant gap exists in population-based longitudinal data for KS from infancy to adulthood.
• Antenatal NIPT is increasing KS identification, but clinical data remains limited.
• Ascertainment bias has historically skewed the understanding of KS's phenotypic spectrum.

Conclusions:

• Longitudinal data is crucial for accurate genetic counseling regarding Klinefelter syndrome.
• Addressing data deficiencies will aid prospective parents and clinicians in managing KS.
• A comprehensive understanding of KS requires data beyond clinical ascertainment.