INTRODUCTION: Wiskott-Aldrich syndrome (WAS) is an inborn error of immunity whose pattern of hereditary transmission is linked to the X chromosome. This syndrome is caused by mutations in the gene that encodes the Wiskott-Aldrich syndrome protein (WASP), which it is a key regulator of cytoskeletal signaling and reorganization in hematopoietic cells. WASP mutations give rise to a broad clinical spectrum ranging from thrombocytopenia, immunodeficiency, eczema, and high susceptibility to tumor development and autoimmune manifestations.

CASE REPORT: We present a clinical case in a 2 years-old-child without consanguinity or inbreeding, who started at 7 moths old with thrombocytopenia with borderline platelet volumes, absolute normal lymphocyte count, flow cytometry with CD8+ count in lower limiting value, normal immunoglobulin serum levels, normal bone marrow aspirate and no history of recurrent infections or dermatitis; Without response to treatment with the use of steroids and disease-modifying drug such as mycophenolate mofetil, and low response to the use of IgGIV. In whom the diagnosis of WAS and isolated thrombocytopenia with a variant of uncertain significance throught a genetic panel Invitae type c.88_90del (p.His30del) in the WAS gene was integrated. The patient is currently receiving IgGIV monthly dose and awaiting a bone marrow transplant at a tertiary-level hospital.

DISCUSSION: We present a case with a variant not documented as pathogenic in a patient with WAS and isolated thrombocytopenia with the purpose of reporting the case so that it can contribute to the reclassification of this variant and thus, in the future, be reclassifying pathogenic; In addition, to have epidemiological records in our country. This variant, results in the deletion of 1 amino acid of the WAS protein, but otherwise preserves the integrity of the reading frame.