Rare diseases · Sign or symptom
Decreased circulating IgG concentration
HP:0004315
What it means
An abnormally decreased level of immunoglobulin G (IgG) in blood.
Rare diseases that can present with this21
Very common80–99%
3Common30–79%
6- Autoimmune lymphoproliferative syndrome due to CTLA4 haploinsuffiency
- Bloom syndrome
- T-B+NK+ severe combined immunodeficiency due to CD3delta/CD3epsilon/CD3zeta deficiency
- T-B-NK+ severe combined immunodeficiency due to DCLRE1C deficiency
- T-B+NK- severe combined immunodeficiency due to gamma chain deficiency
- Transcobalamin II deficiency
Sometimes5–29%
12- Autoimmune lymphoproliferative syndrome
- Hypohidrotic ectodermal dysplasia with immunodeficiency
- MGAT2-CDG
- MOGS-CDG
- Mucopolysaccharidosis-like syndrome with congenital heart defects and hematopoietic disorders
- Primary intestinal lymphangiectasia
- Recurrent infections associated with rare immunoglobulin isotypes deficiency
- Say-Barber-Miller syndrome
and 4 more in this range
The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions, and Orphanet separately records 1 disease where this sign is specifically absent. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Also called: Decreased circulating IgG level · Decreased gamma-globin expression · Decreased IgG level · Decreased IgG level in blood · Decreased immunoglobulin G · Decreased serum IgG · IgG deficiency · Reduced IgG levels
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Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.