A simple screening method for detection of Klinefelter syndrome and other X-chromosome aneuploidies based on copy number of the androgen receptor gene

• Published in: Molecular human reproduction Vol. 13; no. 10; pp. 745 - 750
• Main Authors: Ottesen, A.M., Garn, I.D., Aksglaede, L., Juul, A., Rajpert-De Meyts, E.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.10.2007; Oxford Publishing Limited (England)
• Subjects: Aneuploidy; Biological and medical sciences; Chromosomes, Human, X - genetics; Embryology: invertebrates and vertebrates. Teratology; Female; Fundamental and applied biological sciences. Psychology; Gene Dosage; Humans; In Situ Hybridization, Fluorescence; Karyotyping; Klinefelter syndrome; Klinefelter Syndrome - diagnosis; Klinefelter Syndrome - genetics; Male; Polymerase Chain Reaction - methods; qPCR technique; Receptors, Androgen - genetics; RNA, Long Noncoding; RNA, Untranslated - genetics; screening; X-chromosome; Klinefelter syndrome; qPCR technique; X-chromosome; screening; Chromosomal aberration; Endocrinopathy; Human; Cardiovascular disease; Metabolic diseases; Aneuploidy; Sexual differentiation disorder; Supernumerary X chromosome; Medical screening; Screening; Gene; Number; Malformation; X Syndrome; X-Chromosome; Technique; Detection; Male genital diseases; Hormonal receptor
• ISSN: 1360-9947; 1460-2407
• DOI: 10.1093/molehr/gam053

Due to the high prevalence and variable phenotype of patients with Klinefelter syndrome, there is a need for a robust and rapid screening method allowing early diagnosis. Here, we report on the development and detailed clinical validation of a quantitative real-time PCR (qPCR)-based method of the copy number assessment of the androgen receptor (AR) gene, located to Xq11.2–q12. We analysed samples from 50 individuals, including a healthy male and female controls and patients with Klinefelter syndrome (47,XXY; 48,XXXY) (n = 28), mosaicisms (46,XX/47,XXY/48XXYY; 45,X/46,XY) (n = 3), other sex chromosome abnormalities (46,XX males; 47,XYY)(n = 4) and normal karyotypes (46,XY) (n = 13). The reference range for the AR-copy number was established as 0.8–1.2 for one copy and 1.7–2.3 for two copies. The qPCR results were within the reference range in 17/18 samples (94%) or 30/31 (97%) samples with one or two copies of the AR gene, respectively. None of the Klinefelter patients were misdiagnosed as having a karyotype with only one X-chromosome, and in none of the 46,XY males were two copies demonstrated. We systematically compared qPCR results with those obtained with another PCR-based method, the XIST-gene expression. The XIST-expression based assay was correct in only 29/36 samples (81%). Our findings demonstrated that the AR-qPCR technique is a simple and reliable screening method for diagnosis of patients with Klinefelter syndrome or other chromosomal disorders involving an aberrant number of X-chromosomes.