Wiskott-Aldrich Syndrome in a Two-Month-Old Boy Presenting with Intussusception and Normal-Sized Platelets.
Monday, March 7, 2016
South Exhibit Hall H (Convention Center)
Vanessa L. Bundy, MD, PhD, FAAP, Maria Garcia-Lloret, MD, FAAAAI
Rationale: Wiskott-Aldrich Syndrome (WAS) is an X-linked disorder caused by mutations in the WAS protein gene. Clinical manifestations are variable and frequently the diagnosis is delayed. We report a case with a unique presentation to highlight the importance of a maintaining a high index of clinical suspicion when evaluating an infant with early onset thrombocytopenia and bloody stools. Methods: none. Results:  Two-month-old boy who presented with a one-month history of intermittent fussiness and hematochezia, presumed secondary to cow’s milk protein allergy. He was otherwise well and thriving. Physical exam was normal, other than rectal bleeding and seborrheic dermatitis. Initial labs showed anemia, decreased platelets of normal size, normal white cell count with eosinophilia, no inflammatory markers and negative stool cultures. Ultrasound identified intussusception that was successfully reduced with Gastrografin enema. He then developed fever with tachypnea and was found to have staphylococcus bacteremia and cytomegalovirus viremia. Quantitative immunoglobulins, T & B cell subsets and neutrophil oxidase burst assay were normal. Lymphocytes proliferated briskly to mitogens but not antigens. NK cell function was absent. Gene sequencing identified a hemizygous c.336delC variant in the WAS gene resulting in complete absence of lymphocyte WAS protein expression. Conclusions: More than 300 gene variants have been described in WAS. Mutations leading to absent WAS protein expression are associated with profound immunodeficiency and/or hemorrhagic disease, resulting in decreased survival. In cases like the one presented herein, prompt diagnosis and molecular identification are key, since early bone marrow transplantation can be curative.