Boy with 47,XXY,del(15)(q11.2q13) karyotype and Prader-Willi syndrome: a new case and review of the literature.

We report on a 10-year-old boy with a 47,XXY,del(15)(q11.2q13) karyotype and a Prader-Willi syndrome phenotype. His medical history and physical examination conformed to all of the major clinical criteria for Prader-Willi syndrome, but his height was taller than expected based on his hand and foot sizes. The deleted chromosome 15 was paternal in origin and molecular analysis showed maternal origin for the additional X chromosome. These findings suggest that the presence of these two disorders was coincidental in our patient. This supports the findings in the two other 47,XXY and Prader-Willi cases for which parent of origin studies have been published. Given the information from the literature and presented herein, we suggest that genetic counseling for cases of PWS and 47,XXY should address these two conditions separately.