Objective: There is a paucity of knowledge regarding the prenatal presentation of Klinefelter syndrome, or 47, XXY. Accurate prenatal counseling is critical and in utero diagnosis is currently limited by a poor understanding of the prenatal phenotype of this condition.Methods: This is a case series of fetuses with cytogenetically confirmed 47, XXY in the prenatal period or up to age 5 years, with prenatal records available for review from four academic institutions between 2006 and 2019. Ultrasound reports were reviewed in detail to assess for increased nuchal translucency and structural abnormalities. Additionally, we reviewed results of cell-free DNA and serum analyte testing when performed to inform our understanding of the detection of fetal 47, XXY through standard genetic screening tests.Results: Forty-one cases with confirmed cytogenetic diagnosis of 47, XXY and prenatal records available for review were identified: 37 had a prenatal diagnosis and 4 had a postnatal diagnosis. Nuchal translucency was increased ≥3.0 mm in 23.1% (6/26) of cases with a documented measurement. In 29.2% (7/24) of cases with a second trimester anatomical ultrasound available for review, a fetal abnormality was identified (3 brain anomalies, 1 cardiac abnormality, 1 echogenic bowel, and 2 limb abnormalities). Among those who had cell-free DNA and serum analytes performed, 92.6% (25/27) and 36.3% (4/11) had an abnormal result respectively.
Conclusion:This case series expands our knowledge of the prenatal presentation of 47, XXY by identifying first and second trimester fetal sonographic abnormalities.
During the first decade of the 21 st century, the landscape of epilepsy genetics started to take shape with the discovery of many new genes linked to epilepsy. These genetic discoveries advanced our understanding of the molecular and cellular pathways involved in epilepsy. Over the following ten Note to the Reader: This chapter is part of the book Epilepsy (ISBN: 978-0-6453320-4-9), scheduled for publication in March 2022. The book is being published by Exon Publications,
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