A rare variant Klinefelter syndrome seen 40 years later: 47,X,del(Xq24),Y

Abstract

Klinefelter syndrome (KS) is the most common sex chromosome aneuploidy in humans, characterised by an extra X-chromosome. Its estimated incidence is one in every 500-1,000 births (Lanfranco et al., 2004). It is one of the most common reasons for nonobstructive azoospermia (Takeda et al., 2017). Patients affected by KS are usually characterised by narrow shoulders, sparse body, tall stature, facial hair, gynecomastia and normal to slightly lower intelligence.In addition, these patients may have clinical symptoms including infertility, low testosterone levels, increased serum follitropin (FSH) and lutropin (LH) values, high thromboembolic risk, osteoporosis and azoospermia (Bojesen & Gravholt, 2007).Klinefelter syndrome patients typically show the 47,XXY karyotype. However, some variations have been observed including 47,XX,der(Y), 46,XY/47,XXY, 48,XXXY, 48,XXYY and mosaicism or structural sex chromosome abnormalities in some patients (Fruhmesser & Kotzot, 2011).In the literature, a rare KS variant, 47,X,del(Xq),Y karyotype,