Traits

Traits linked to HBB

hemoglobin subunit beta

The Human Phenotype Ontology links 134 traits to HBB, by body system: features seen in people with one of the gene's rare conditions.

HBB

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Chronic hemolytic anemia	Always
Decreased mean corpuscular hemoglobin concentration	Always
Erythrocyte inclusion bodies	Always
Increased circulating hemoglobin concentration	Always
Increased HbA2 hemoglobin	Always
Increased hematocrit	Always
Increased red blood cells	Always
Microcytic anemia	Always
Persistence of hemoglobin F	Always
Abnormal hemoglobin	Very often (80–99%)
Anemia of inadequate production	Very often (80–99%)
Anisopoikilocytosis	Very often (80–99%)
Decreased mean corpuscular volume	Very often (80–99%)
Hemolytic anemia	Very often (80–99%)
Hypochromia	Very often (80–99%)
Hypochromic microcytic anemia	Very often (80–99%)
Imbalanced hemoglobin synthesis	Very often (80–99%)
Increased red blood cell count	Very often (80–99%)
Low number of red blood cells or hemoglobin	Very often (80–99%)
Reduced hemoglobin A	Very often (80–99%)
Elevated white blood count	Often (30–79%)
Erythroid hyperplasia	Often (30–79%)
Extramedullary hematopoiesis	Often (30–79%)
HbS hemoglobin	Often (30–79%)
Hypercoagulability	Often (30–79%)
Increased immature red blood cells	Often (30–79%)
Increased number of platelets in blood	Often (30–79%)
Iron deficiency anemia	Often (30–79%)
Reduced alpha/beta synthesis ratio	Often (30–79%)
Reduced beta/alpha synthesis ratio	Often (30–79%)
Unequal size of red blood cells	Often (30–79%)
Blood clot in vein	Sometimes (5–29%)
Drug-sensitive hemolytic anemia	Sometimes (5–29%)
Hyphema	Sometimes (5–29%)
Increased red cell osmotic resistance	Sometimes (5–29%)
Increased red cell sickling tendency	Sometimes (5–29%)
Sickled erythrocytes	Sometimes (5–29%)
Hypochromic anemia	Rarely (1–4%)
Increased mean corpuscular volume	Rarely (1–4%)
Heinz bodies	Not recorded
Heinz body anemia	Not recorded
Methemoglobinemia	Not recorded
Nonspherocytic hemolytic anemia	Not recorded
Target cells	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
Increased spleen size	Always
Abnormality of the spleen	Often (30–79%)
Hypersplenism	Often (30–79%)
Abnormality of the cardiovascular system	Sometimes (5–29%)
Abnormality of the vasculature	Sometimes (5–29%)
Absent spleen	Sometimes (5–29%)
Enlarged liver and spleen	Sometimes (5–29%)
High-output congestive heart failure	Sometimes (5–29%)
Increased blood pressure in blood vessels of lungs	Sometimes (5–29%)
Ischemic stroke	Sometimes (5–29%)
Splenic infarction	Sometimes (5–29%)
Stretched and thinned heart muscle	Sometimes (5–29%)
Abnormal heart rate	Rarely (1–4%)
Enlarged heart	Not recorded
High blood pressure	Not recorded
Stroke	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Enlarged liver	Always
Feeding difficulties	Often (30–79%)
Jaundice	Often (30–79%)
Pigment gallstones	Often (30–79%)
Abdominal pain	Sometimes (5–29%)
Abnormality of the liver	Sometimes (5–29%)
Chronic liver inflammation	Sometimes (5–29%)
Decreased liver function	Sometimes (5–29%)
Diarrhea	Sometimes (5–29%)
Gallstones	Sometimes (5–29%)
Hepatic fibrosis	Sometimes (5–29%)
Impaired release of bile from liver	Sometimes (5–29%)
Scar tissue replaces healthy tissue in the liver	Sometimes (5–29%)
Hepatocellular carcinoma	Rarely (1–4%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Osteoporosis	Very often (80–99%)
Abnormal bone structure	Often (30–79%)
Abnormality of the skeletal system	Often (30–79%)
Abnormally shaped skeletal	Often (30–79%)
Death of bone due to decreased blood supply	Often (30–79%)
Increased susceptibility to fractures	Often (30–79%)
Low solidness and mass of the bones	Often (30–79%)
Poorly developed skeletal musculature	Often (30–79%)
Osteopenia	Sometimes (5–29%)

Laboratory abnormality

Trait	How often it is seen
Abnormality of iron homeostasis	Often (30–79%)
Diabetes mellitus	Sometimes (5–29%)
Elevated creatinine	Sometimes (5–29%)
Episodic fever	Sometimes (5–29%)
Increased circulating lactate dehydrogenase concentration	Sometimes (5–29%)
Increased iron concentration in liver	Sometimes (5–29%)
Unconjugated hyperbilirubinemia	Sometimes (5–29%)
Blood in urine	Not recorded

Abnormality of head or neck

Trait	How often it is seen
Abnormal dentition	Often (30–79%)
Big maxilla	Sometimes (5–29%)
Depressed nasal bridge	Sometimes (5–29%)
Frontal bossing	Sometimes (5–29%)
Malar prominence	Sometimes (5–29%)
Retinal arterial occlusion	Sometimes (5–29%)
Upward slanting of the opening between the eyelids	Sometimes (5–29%)

Abnormality of the endocrine system

Trait	How often it is seen
Decreased parathyroid hormone secretion	Sometimes (5–29%)
Delayed puberty	Sometimes (5–29%)
Hypopituitarism	Sometimes (5–29%)
Underactive thyroid	Sometimes (5–29%)
Adrenal insufficiency	Rarely (1–4%)
Decreased activity of gonads	Rarely (1–4%)

Abnormality of the immune system

Trait	How often it is seen
Recurrent infections	Very often (80–99%)
Bone infection	Often (30–79%)
Chronic infection	Sometimes (5–29%)
Severe infection	Sometimes (5–29%)
Recurrent bacterial infections	Not recorded

Abnormality of the genitourinary system

Trait	How often it is seen
Chronic kidney disease	Often (30–79%)
Priapism	Sometimes (5–29%)
Proximal tubulopathy	Sometimes (5–29%)
Renal failure	Not recorded

Abnormality of the integument

Trait	How often it is seen
Paleness	Very often (80–99%)
Open skin sore	Often (30–79%)
Patchy darkened skin	Often (30–79%)
Blue discoloration of the skin	Not recorded

Abnormality of limbs

Trait	How often it is seen
Bowing of the long bones	Often (30–79%)
Knock knees	Often (30–79%)
Sausage fingers	Sometimes (5–29%)

Abnormality of the nervous system

Trait	How often it is seen
Abnormality of the nervous system	Sometimes (5–29%)
Irritability	Sometimes (5–29%)
Pressure on spinal cord	Rarely (1–4%)

Abnormality of the respiratory system

Trait	How often it is seen
Breathing difficulty	Often (30–79%)
Low blood oxygen level	Sometimes (5–29%)
Lung infiltrates	Sometimes (5–29%)

Constitutional symptom

Trait	How often it is seen
Pain	Very often (80–99%)
Chest pain	Often (30–79%)
Joint pain	Sometimes (5–29%)

Growth abnormality

Trait	How often it is seen
Faltering weight in infancy	Often (30–79%)
Growth delay	Often (30–79%)
Prenatal growth deficiency	Sometimes (5–29%)

Abnormality of prenatal development or birth

Trait	How often it is seen
Premature birth	Sometimes (5–29%)

Abnormality of the eye

Trait	How often it is seen
Noninflammatory retina disease	Often (30–79%)

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 HBB and how often each is seen. Find out more at hpo.jax.org.

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