Affected Males
Bleeding disorder. Males typically present in infancy with a bleeding disorder. Affected individuals have easy bruising and mucosal bleeding (e.g., gingival bleeding, epistaxis). Petechiae, ecchymoses, and/or splenomegaly may be identified on physical examination. Excessive hemorrhage and/or bruising can occur either spontaneously or after trauma or surgery. Fetal cerebral hemorrhage with in utero demise has been reported [Bouchghoul et al 2018].
Platelet counts are usually low (10-100 x 103/µL) but can vary considerably. Normal platelet counts have also been reported (150-400 x 103/µL), including in individuals with a germline pathogenic variant resulting in a truncated protein (GATA-1s; see Molecular Genetics) causing congenital anemia [Hollanda et al 2006, Sankaran et al 2012]. The platelets are typically larger than normal (macrothrombocytopenia) and more spherical than the typical discoid morphology [Crispino & Horwitz 2017, Bouchghoul et al 2018]. Platelets may be pale, reflecting reduced granularity.
Anemia. Individuals with anemia may present with fatigue or pallor; anemia may also be incidentally identified on a complete blood count (CBC) obtained for other reasons. Hematocrit ranges from 16% to 35% (normal: 35%-45%). Red cell indices on CBC typically show normochromic cells that may be mildly microcytic (75-79 fL) or macrocytic (101-103 fL) (normal: 80-99 fL). On peripheral blood smear there is variation in erythrocyte size and shape and hypochromia, reflecting low hemoglobin content.
The severity of anemia ranges from mild dyserythropoiesis to severe hydrops fetalis requiring in utero transfusions [Crispino & Horwitz 2017, Bouchghoul et al 2018, Abdulhay et al 2019].
GATA1 pathogenic variants affecting p.Arg307 (c.919C>T [p.Arg307Cys] and c.920G>A [p.Arg307His]) were identified in four male probands with hemolytic anemia, mild thrombocytopenia, and reticulocytosis, with elevated adenosine deaminase and bone marrow erythroid hyperplasia [Hetzer et al 2022, Ludwig et al 2022]. A beta-thalassemia-like phenotype with globin chain imbalance has been reported in association with the GATA1 variant p.Arg216Gln, but the anemia and reticulocytosis were accompanied by thrombocytopenia and a coagulopathy, suggesting that this is a distinct disease from beta-thalassemia [Yu et al 2002].
GATA1 pathogenic variants have been identified in individuals previously diagnosed with Diamond-Blackfan anemia (see Nomenclature). Pathogenic frameshift or nonsense variants in GATA1 that result in the exclusive production of an amino terminus-truncated protein termed GATA-1 short (GATA-1s) (e.g., c.2T>C, c.3G>A) have been identified in several unrelated probands with pure red cell aplasia and additional clinical features of Diamond-Blackfan anemia [Sankaran et al 2012, Klar et al 2014, Ludwig et al 2014, Parrella et al 2014, Zucker et al 2016, Chen et al 2022, Hasle et al 2022, van Dooijeweert et al 2022]. Diamond-Blackfan anemia is typically associated with heterozygous pathogenic variants in ribosomal protein-encoding genes and is characterized by profound normochromic and usually macrocytic anemia with normal leukocytes and platelets, congenital malformations in up to 50% of affected individuals, and growth deficiency in 30% of individuals. For individuals with GATA1 pathogenic variants the accurate diagnosis is GATA1-related cytopenia.
Rarely, GATA1-related cytopenia can progress to myelodysplasia and myelodysplastic syndrome or aplastic anemia [Kratz et al 2008; Authors, unpublished data].
Neutropenia. Persistent neutropenia (0.5-1.0 x 103/µL; normal: 1.9-8.0 x 103/µL) with abnormal neutrophil morphology was observed in some affected males in one family [Hollanda et al 2006]; variable neutrophil counts have been reported in other affected individuals [Hollanda et al 2006, Sankaran et al 2012, Zucker et al 2016, Svidnicki et al 2021]. Individuals with severe neutropenia may be predisposed to severe bacterial infections [Hollanda et al 2006].
Splenomegaly has been reported in some individuals with GATA1-related cytopenia (see Genotype-Phenotype Correlations).
Cryptorchidism and hypospadias have been reported [Bouchghoul et al 2018, Kobayashi et al 2022]. Typically, no other congenital anomalies are present in individuals with GATA1-related cytopenia.
Course and prognosis