Bobby is 3 years old and has Down’s syndrome and Atrial Septal Defect (surgically corrected). His mother brings him to see his GP as she is concerned that he has multiple unexplained bruises all over his arms and legs. There is no history of injury and his mother is unaware of any other systemic symptoms, reduced appetite or weight loss. On examination, Bobby appears happy and is interacting well with his mother. He has widespread bruising on his arms and legs and cervical and inguinal lymphadenopathy is noted.
Given the likely diagnosis what is the next most appropriate course of action?