Prenatal Diagnosis of Double Aneuploidy, 48,XXY,+21, and Review of the Literature

We present a case of prenatally diagnosed double aneuploidy with an additional chromosome 21 characteristic of Down syndrome and an additional XXY complement characteristic of Klinefelter syndrome. Sonographic findings were suggestive of Down syndrome: absent nasal bone, bilateral brachymesophalangia of the fifth digit, prominent but normal lateral ventricles, and a short femur and humerus for gestational age. Despite postnatal complications, the child was alive and well at 19 months of age. A review of the literature was performed to determine the prevalence, prenatal mortality rate, phenotype, and sonographic findings reported in other cases of Down-Klinefelter double aneuploidy.