Traits

Traits linked to HBA2

hemoglobin subunit alpha 2

The Human Phenotype Ontology links 52 traits to HBA2, by body system: features seen in people with one of the gene's rare conditions.

HBA2

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Abnormal hemoglobin	Very often (80–99%)
HbH hemoglobin	Very often (80–99%)
Low number of red blood cells or hemoglobin	Very often (80–99%)
Microcytic anemia	Very often (80–99%)
Bruising susceptibility	Often (30–79%)
Heinz bodies	Not recorded
Heinz body anemia	Not recorded
Hemolytic anemia	Not recorded
Hypochromic microcytic anemia	Not recorded
Increased circulating hemoglobin concentration	Not recorded
Increased hematocrit	Not recorded
Increased red blood cells	Not recorded
Nonspherocytic hemolytic anemia	Not recorded
Reduced alpha/beta synthesis ratio	Not recorded

Abnormality of head or neck

Trait	How often it is seen
Abnormally small head	Often (30–79%)
Broad forehead	Often (30–79%)
Downward slanting of the opening between the eyelids	Often (30–79%)
Eye folds	Often (30–79%)
High forehead	Often (30–79%)
High palate	Often (30–79%)
Little lower jaw	Often (30–79%)
Receding chin	Often (30–79%)
Short neck	Often (30–79%)
Wide nasal bridge	Often (30–79%)
Zygomatic flattening	Often (30–79%)
Flattened bony protrusion above eyes	Sometimes (5–29%)
Frontal bossing	Sometimes (5–29%)
Sparse or absent eyebrows	Sometimes (5–29%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Cardiac failure	Very often (80–99%)
Increased spleen size	Often (30–79%)
Swelling or irritation of membrane around heart	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Low muscle tone	Often (30–79%)
Pigeon chest	Often (30–79%)
Flexed joint that cannot be straightened	Sometimes (5–29%)

Abnormality of the nervous system

Trait	How often it is seen
Abnormal speech pattern	Very often (80–99%)
Intellectual disability	Very often (80–99%)
Too much cerebrospinal fluid in the brain	Often (30–79%)

Abnormality of limbs

Trait	How often it is seen
Club feet	Often (30–79%)
Short toe	Often (30–79%)

Abnormality of prenatal development or birth

Trait	How often it is seen
High levels of amniotic fluid	Often (30–79%)
Low levels of amniotic fluid	Often (30–79%)

Abnormality of the ear

Trait	How often it is seen
Absent/small ear lobes	Often (30–79%)
Ears rotated toward back of head	Often (30–79%)

Abnormality of the genitourinary system

Trait	How often it is seen
Undescended testes	Often (30–79%)
Hypospadias	Sometimes (5–29%)

Growth abnormality

Trait	How often it is seen
Faltering weight	Often (30–79%)
Short stature	Often (30–79%)

Abnormality of the digestive system

Trait	How often it is seen
Enlarged liver	Often (30–79%)

Abnormality of the eye

Trait	How often it is seen
Wide-set eyes	Often (30–79%)

Abnormality of the integument

Trait	How often it is seen
Paleness	Very often (80–99%)

Constitutional symptom

Trait	How often it is seen
Fatigue	Very often (80–99%)

Laboratory abnormality

Trait	How often it is seen
Hydrops fetalis	Very often (80–99%)

How often is among people with one of the gene's conditions, the most often across them, as the Human Phenotype Ontology records it. These pages describe traits and the research behind them; they are not a diagnosis, and a doctor or genetic counsellor is the person to ask about symptoms.

Where this comes from

The Human Phenotype Ontology, release 2026-09-01: the traits linked to HBA2 and how often each is seen. Find out more at hpo.jax.org.

One test. A lifetime of answers.

From $449Free shipping · Results in 6–8 weeks

Get my Genome Test