Complement component C1s deficiency

Congenital, selective C1s complement deficiency leading to multiple autoimmune diseases already in childhood. Clinically, there is an association with systemic lupus erythematosus (Uchio-Yamada K et al. 2019) and lupus erythematosus-like phenomena (Inoue et al. 1998) with glomeulonephritis. The correlations have not yet been clarified.

Selective C1s deficiency due to a homozygous mutation in the C1S gene (120580.0001).

Inoue et al (1998) reported a patient with a systemic lupus erythematosus-like syndrome and chronic glomerulonephritis in whom C1s protein was undetectable by immunoblot.

Dragon-Durey et al (2001) demonstrated selective C1S deficiency in a 27-month-old girl with multiple autoimmune diseases, which was due to a nonsense mutation in exon 12 of the C1S gene (120580.0002). The mutation was not detected in patients with systemic lupus erythematosus (152700) or in unrelated Caucasian control subjects, including some from the same geographic region.

1. Dragon-Durey et al (2001) Molecular basis of a selective C1s deficiency associated with early onset multiple autoimmune diseases. J Immun 166: 7612-7616.
2. Inoue N et al (1998) Selective complement C1s deficiency caused by homozygous four-base deletion in the C1s gene. Hum Genet 103: 415-418.
3. Uchio-Yamada K et al (2019) C1r/C1s deficiency is insufficient to induce murine systemic lupus erythematosus. Genes Immun 20:121-130.