MHC class II deficiency
Findings
No curated finding names MHC class II deficiency yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Immunodeficiency by defective expression of HLA class 2 is a rare primary genetic immunodeficiency disorder characterized by partial or complete absence of human leukocyte antigen class 2 expression resulting in severe defect in both cellular and humoral immune response to antigens. The disorder presents clinically as marked susceptibility to infections, severe malabsorption and failure to thrive and is often fatal in early childhood.
Definition from the Mondo Disease Ontology (MONDO:0008855), read 2026-09-29. CC BY 4.0.
Features
38 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- Reduced MHC II cell surface expressionHPOHP:0031390
- Obligate (100% of cases)
- Abnormal T cell physiologyHPOHP:0011840
- Very frequent (80% to 99% of cases)
- Recurrent infection of the gastrointestinal tractHPOHP:0004798
- Very frequent (80% to 99% of cases)
- Recurrent respiratory infectionsHPOHP:0002205
- Very frequent (80% to 99% of cases)
- Abnormality of humoral immunityHPOHP:0005368
- Frequent (30% to 79% of cases)
- Chronic hepatitis due to cryptosporidium infectionHPOHP:0200124
- Frequent (30% to 79% of cases)
Show the remaining 26
- Recurrent bacterial infectionsHPOHP:0002718
- Frequent (30% to 79% of cases)
- Recurrent Candida infectionHPOHP:0005401
- Frequent (30% to 79% of cases)
- Recurrent fungal infectionsHPOHP:0002841
- Frequent (30% to 79% of cases)
- Recurrent herpesHPOHP:0005353
- Frequent (30% to 79% of cases)
- Recurrent mucocutaneous candidiasisHPOHP:0002728
- Frequent (30% to 79% of cases)
- Recurrent protozoan infectionsHPOHP:0005386
- Frequent (30% to 79% of cases)
Genes
4 genes
Germline variants in the gene encoding each protein, as classified by GenCC submitters, each in their own words. Limited, disputed and refuted submissions are listed too.
- CIITAHGNC:7067
- Definitive · ClinGen · Autosomal recessive · 2022
- Definitive · Natera · Autosomal recessive · 2022
- Strong · Labcorp Genetics (formerly Invitae) · Autosomal recessive · 2018
- Supportive · Orphanet · Autosomal recessive · 2021
- RFX5HGNC:9986
- Definitive · Ambry Genetics · Autosomal recessive · 2024
- Definitive · ClinGen · Autosomal recessive · 2023
- Strong · Labcorp Genetics (formerly Invitae) · Autosomal recessive · 2018
- Supportive · Orphanet · Autosomal recessive · 2021
- RFXANKHGNC:9987
- Definitive · ClinGen · Autosomal recessive · 2022
- Strong · Labcorp Genetics (formerly Invitae) · Autosomal recessive · 2021
Where it sits
Other names
5 names
Resolves to: MHC class II deficiency
- Also called
- HLA class 2-negative SCIDHLA class 2-negative severe combined immunodeficiencyimmunodeficiency by defective expression of HLA class type 2major histocompatibility complex class II expression deficiencyMHC class II expression deficiency