Prenatal ultrasound diagnosis of a 48,XXYY syndrome

The 48,XXYY syndrome is a rare uncommon gonosome aneuploidy and its incidence is estimated to be 1:18,000-1:40,000. The phenotype associated with this syndrome, classically described as Klinefelter variant, is extremely variable but developmental abnormalities are always present. Ultrasound signs during pregnancy are inconsistent, and only three prenatal cases have been described in the literature. Here, we report a case of 48,XXYY syndrome identified in prenatal period because of the presence of polyhydramnios and bilateral clubfeet on second trimester ultrasound. This observation shows the importance of chromosomal prenatal diagnosis in cases with bilateral clubfeet on morphologic ultrasound. This diagnosis is essential for further characterization of the prenatal phenotype and to improving genetic counselling.