Increased MAP-1 and lectin complement activation capacity in Klinefelter syndrome
Simon Chang1,2,3,4, Jesper Just3,4, Anne Skakkebæk3,4,5
1Department of Endocrinology, Aarhus University Hospital, 8200 Aarhus N, Denmark.
The Journal of Clinical Endocrinology and Metabolism
|March 24, 2026
Summary
Men with Klinefelter syndrome (KS) show heightened lectin complement pathway activation and elevated MAP-1 and MASP1-201 expression, indicating altered immune function that may contribute to disease risks.
Area of Science:
- Immunology
- Genetics
- Endocrinology
Background:
- Klinefelter syndrome (KS) is associated with immune dysregulation and metabolic issues.
- Individuals with KS have an increased risk of autoimmune, metabolic, and cardiovascular diseases.
Purpose of the Study:
- To investigate lectin pathway complement activation in men with KS.
- To explore relationships between complement activation, hypogonadism, body composition, and fibrinolysis in KS.
Main Methods:
- Cross-sectional study comparing 45 men with KS to 45 age-matched controls.
- ELISAs measured lectin pathway activation, complement factors (MAP-1), and C3dg.
- Body composition assessed by DXA; fibrinolysis by turbidometry.
- Skeletal muscle MASP1 gene splice variant MASP1-201 expression analyzed.
Main Results:
- Lectin pathway activation capacity was significantly higher in men with KS (106.2 ± 51.6%) versus controls (64.0 ± 30.1%).
- Elevated serum MAP-1 and increased MASP1-201 expression were observed in KS.
- Lectin pathway contributed to fibrin clot lysis variability in KS; no difference in C3dg levels.
Conclusions:
- Men with KS exhibit enhanced lectin complement pathway activation and increased MAP-1 and MASP1-201 expression.
- Altered immune function, specifically via the lectin pathway, may be a characteristic of KS.
- This immune alteration could contribute to the increased comorbidity burden in KS.
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