- Persistence of hemoglobin F (HP:0011904): Hemoglobin F (HbF) contains two globin alpha chains and two globin gamma chains. It is the main form of hemoglobin in the fetus during the last seven months of intrauterine development and in the half year of postnatal life. In adults it normally makes up less than one percent of all hemoglobin. This term refers to an increase in HbF above this limit. In beta thalassemia major, it may represent over 90 percent of all hemoglobin, and in beta thalassemia minor it may make up between 0.5 to 4 percent. Evidence: PCS. Frequency: 1/1. (PMID:15977037)
- Hepatomegaly (HP:0002240): Abnormally increased size of the liver. Evidence: PCS. Frequency: 1/1. (PMID:15977037)
- Increased HbA2 hemoglobin (HP:0045048): An elevated concentration in the blood of hemoglobin A2 (HbA2), which is a normal variant of hemoglobin A that consists of two alpha and two delta chains and is normally present at low levels in adults but may be increased in beta thalassemia. Evidence: PCS. Frequency: 1/1. (PMID:15977037)
- Decreased mean corpuscular hemoglobin concentration (HP:0025547): A reduction from the normal range of the average amount of hemoglobin per red blood cell (27 to 31 picograms/cell). A reduced mean corpuscular hemoglobin (MCH) may indicate a hypochromic anemia, but the MCH may be normal if both the total hemoglobin and the red blood cell count are reduced. Evidence: PCS. Frequency: 1/1. (PMID:15977037)
- Microcytic anemia (HP:0001935): A kind of anemia in which the volume of the red blood cells is reduced. Evidence: PCS. Frequency: 1/1. (PMID:15977037)
- Autosomal dominant inheritance (HP:0000006): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele. Evidence: PCS. (PMID:15977037)
- Splenomegaly (HP:0001744): Abnormal increased size of the spleen. Evidence: PCS. Frequency: 1/1. (PMID:15977037)
- Erythrocyte inclusion bodies (HP:0020080): Nuclear or cytoplasmic aggregates of substances in red blood cells. Evidence: PCS. Frequency: 1/1. (PMID:15977037)
These phenotypes are associated with the disease dominant beta-thalassemia (OMIM:603902).