- Persistence of hemoglobin F (HP:0011904, a Human Phenotype Ontology term): 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. (PMID:17186470)
- Increased mean corpuscular volume (HP:0005518, a Human Phenotype Ontology term): Larger than normal size of erythrocytes. Evidence: PCS. (PMID:17186470)
- Reticulocytopenia (HP:0001896, a Human Phenotype Ontology term): A reduced number of reticulocytes in the peripheral blood. Evidence: PCS. (PMID:17186470)
- Elevated red cell adenosine deaminase activity (HP:0030270, a Human Phenotype Ontology term): Increase in the level of adenosine deaminase (ADA), an enzyme involved in purine metabolism, within erythrocytes. ADA is involved in the catabolism of adenosine. Evidence: PCS. Frequency: 10/10. (PMID:17186470)
- Macrocytic anemia (HP:0001972, a Human Phenotype Ontology term): A type of anemia characterized by increased size of erythrocytes with increased mean corpuscular volume (MCV) and increased mean corpuscular hemoglobin (MCH). Evidence: PCS. (PMID:17186470)
- Webbed neck (HP:0000465, a Human Phenotype Ontology term): Pterygium colli is a congenital skin fold that runs along the sides of the neck down to the shoulders. It involves an ectopic fibrotic facial band superficial to the trapezius muscle. Excess hair-bearing skin is also present and extends down the cervical region well beyond the normal hairline. Evidence: PCS. Frequency: 1/10. (PMID:17186470)
- Autosomal dominant inheritance (HP:0000006, a Human Phenotype Ontology term): 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:17186470)
These phenotypes are associated with the disease Diamond-Blackfan anemia 3 (OMIM:610629, an entry in Online Mendelian Inheritance in Man).