Traits

Traits linked to B2M

beta-2-microglobulin

The Human Phenotype Ontology links 43 traits to B2M, by body system: features seen in people with one of the gene's rare conditions.

Laboratory abnormality

Trait	How often it is seen
Amyloidosis of peripheral nerves	Always
Cardiac amyloidosis	Always
Decreased circulating beta-2-microglobulin concentration	Always
Decreased protein levels in blood	Always
Hepatic amyloidosis	Always
Low albumin	Always
Renal amyloidosis	Often (30–79%)
Cutaneous amyloidosis	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Abnormally shaped muscle	Sometimes (5–29%)
Hip joint pain	Sometimes (5–29%)
Knee pain	Sometimes (5–29%)
Multiple bony cystic lesions	Sometimes (5–29%)
Spontaneous fracture	Sometimes (5–29%)
Wrist pain	Sometimes (5–29%)

Abnormality of the nervous system

Trait	How often it is seen
Peripheral nerve disease	Always
Constrictive median neuropathy	Often (30–79%)
Abnormal autonomic nervous system physiology	Sometimes (5–29%)
Nerve damage causing decreased feeling and movement	Sometimes (5–29%)
Pressure on spinal cord	Sometimes (5–29%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Decrease in blood pressure upon standing up	Always
Abnormal vascular morphology	Sometimes (5–29%)
Cardiovascular calcification	Sometimes (5–29%)
Reduced left ventricular ejection fraction	Sometimes (5–29%)

Abnormality of the digestive system

Trait	How often it is seen
Chronic constipation	Always
Chronic diarrhea	Always
Death of digestive organ tissue due to poor blood supply	Sometimes (5–29%)
Intestinal perforation	Sometimes (5–29%)

Abnormality of the immune system

Trait	How often it is seen
Decreased specific antibody response to unconjugated polysaccharide vaccine	Always
Lung abscess	Often (30–79%)
Recurrent respiratory infections	Not recorded

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Low B cell count	Often (30–79%)
Reduced total natural killer cell count	Often (30–79%)

Abnormality of head or neck

Trait	How often it is seen
Abnormality of the salivary glands	Sometimes (5–29%)
Abnormality of the tongue	Sometimes (5–29%)

Abnormality of limbs

Trait	How often it is seen
Bowing of outer large bone of the forearm	Not recorded
Underdeveloped inner large forearm bone	Not recorded

Abnormality of the respiratory system

Trait	How often it is seen
Permanent enlargement of the airways of the lungs	Always
Organizing pneumonia	Often (30–79%)

Abnormal cellular phenotype

Trait	How often it is seen
Decreased circulating IgG concentration	Always

Abnormality of the genitourinary system

Trait	How often it is seen
Chronic kidney disease	Often (30–79%)

Abnormality of the integument

Trait	How often it is seen
Firm lump under the skin	Often (30–79%)

Constitutional symptom

Trait	How often it is seen
Shoulder pain	Sometimes (5–29%)

Growth abnormality

Trait	How often it is seen
Weight loss	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 B2M and how often each is seen. Find out more at hpo.jax.org.

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