Prader- Willi and Angelman syndromes are caused by which type of chromosomal mutations, both in connection with chromosome 15?

A karyotype shows that a child has Klinefelter syndrome (47,XXY). If the child is also color- blind (due to a recessive X- linked allele), despite his parents having normal color vision, in which parent and stage of meiosis did nondisjunction occur?

When nondisjunction occurs early in embryogenesis rather than gametogenesis, what would you expect in the resulting karyotype?