Rare combination of Becker muscular dystrophy and Klinefelterʹs syndrome in one patient

Becker muscular dystrophy (BMD) was diagnosed in a male patient with Klinefelterʹs syndrome (47, XXY karyotype). The BMD was confirmed by (i) immunohistological methods and Western blotting, showing decreased quantity of dystrophin in muscle biopsy specimen and (ii) molecular genetic analysis which demonstrated a homozygous deletion of exons 45–47 within the dystrophin gene on both X-chromosomes. The same deletion was found on one of the X-chromosomes in the patientʹs mother. It can be deduced therefore that Klinefelterʹs syndrome in this patient is most likely due to a non-disjunctional error which occurred either during the second maternal meiotic division or during early postzygotic mitotic divisions.