June 10th, 2021
A 4-year-old boy presents with worsening unsteadiness while walking and slurring of speech for the past few months. His medical history is significant for recurrent respiratory tract infections for several years. His sister died of overwhelming sepsis at 13 years of age, following a similar illness with recurrent respiratory infections and developmental regression. His parents are apparently normal. His birth history is unremarkable, and all immunizations are up to date.