Objectives Severe congenital neutropenia (SCN) is a primary immunodeficiency (PID) characterized by persistent severe neutropenia, recurrent infections, and oral aphthous lesions. Severe congenital neutropenia is caused by various genetic defects such as ELANE, GFI, HAX-1, JAGN1, SRP54, and glucose-6 phosphatase catalytic subunit 3 (G6PC3) deficiency. Clinical features of the patients with G6PC3 deficiency vary from neutropenia to several systemic features in addition to developmental delay. Case presentation In this report, we presented three unrelated patients diagnosed with G6PC3 deficiency. All these patients had short stature, prominent and superficial vascular tissue, cardiac abnormalities (Atrial septal defect (secondary), mitral valve prolapse with mitral insufficiency, pulmonary hypertension) and lymphopenia. Patient 1 (P1) and 2 (P2) had urogenital abnormalities, P2 and P3 had thrombocytopenia. Conclusions We have shown that lymphopenia and CD4 lymphopenia do not rarely accompany to G6PC3 deficiency. Characteristic facial appearance, systemic manifestions, neutropenia could be the clues for the diagnosis of G6PC3 deficiency.
Keywords: glucose-6 phosphatase catalytic subunit 3; lymphopenia; myeloid maturation arrest; severe congenital neutropenia; thrombocytopenia.