Abstract
Triple X syndrome is the most common sex chromosome aneuploidies (SCA) in females. Still, it is underdiagnosed because patients are usually without clear dysmorphism, and the syndrome is not associated with any significant congenital anomalies. We are reporting a case of a 5-year-old girl who presented with aplastic anemia, confirmed by a bone marrow aspiration and biopsy. Her complete workup showed that she has three copies of chromosome X, which, given the diagnosis of triple X syndrome, requires a supportive treatment but not a bone marrow transplant. Few cases of aplastic anemia with sex chromosome abnormalities have been reported. We are reviewing the triple X syndrome in different aspects of the presentation.