Details of Disease

General Information of Disease (ID: DISWV4KU)

• Disease Name: C1Q deficiency
• Synonyms: C1QD; C1q deficiency; C1Q deficiency
• Definition: C1q deficiency is a rare disorder associated with recurrent skin lesions, chronic infections, systemic lupus erythematosus (SLE) or SLE-like diseases. It has also been associated with a kidney disease known as mesangial proliferative glomerulonephritis. C1q is a complex and together with other proteins, C1r and C1s, it forms the C1 complex. This complex is important for the activation of the complement system (a group of proteins that work with the immune system). It also disposes cells that are dead. C1q deficiency presents in 2 different forms, absent C1q protein or abnormal C1q protein. Symptoms include infections (ear infections (otitis media), meningitis, urinary tract infections, oral infections); skin lesions (small blisters (vesicles), dark patches, and atrophic areas) that get worse upon light exposure; cataracts; loss of eyelashes, eyebrows, and scalp hair; blood in urine; and glomerulonephritis. About 93% of cases are associated with systemic lupus erythematosus. It can be caused by mutations in the C1QA, C1QB or C1QC genes and is inherited in an autosomal recessive pattern. Treatment depends on the symptoms. Recently, it was shown that C1q production can be restored by allogeneic hematopoietic stem cell transplantation, a procedure in which a person receives blood-forming stem cells (cells from which all blood cells develop) from a genetically similar, but not identical donor.
• Disease Hierarchy:
  DISM3M9W: Immunodeficiency due to a classical component pathway complement deficiency
  DISWV4KU: C1Q deficiency
• Disease Identifiers:
  MONDO ID: MONDO_0013343
  UMLS CUI: C3150902
  OMIM ID: 613652
  MedGen ID: 462252

Molecular Interaction Atlas (MIA) of This Disease

This Disease Is Related to 2 DTT Molecule(s)

Gene Name	DTT ID	Evidence Level	Mode of Inheritance	REF
C1QB	TT8A9DM	Strong	Genetic Variation	[1]
C1QB	TT8A9DM	Definitive	Autosomal recessive	[2]

This Disease Is Related to 4 DOT Molecule(s)

Gene Name	DOT ID	Evidence Level	Mode of Inheritance	REF
C1QA	OT6XKVVA	Strong	Autosomal recessive	[3]
C1QC	OTLE5U1P	Strong	Autosomal recessive	[4]
RNPC3	OTW5MKC1	Strong	Biomarker	[5]
C1QB	OT2G1IOX	Definitive	Autosomal recessive	[2]

References

• [1] Identification of a novel non-coding mutation in C1qB in a Dutch child with C1q deficiency associated with recurrent infections.Immunobiology. 2015 Mar;220(3):422-7. doi: 10.1016/j.imbio.2014.10.005. Epub 2014 Oct 18.
• [2] Technical standards for the interpretation and reporting of constitutional copy-number variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics (ACMG) and the Clinical Genome Resource (ClinGen). Genet Med. 2020 Feb;22(2):245-257. doi: 10.1038/s41436-019-0686-8. Epub 2019 Nov 6.
• [3] Molecular basis of hereditary C1q deficiency--revisited: identification of several novel disease-causing mutations. Genes Immun. 2011 Dec;12(8):626-34. doi: 10.1038/gene.2011.39. Epub 2011 Jun 9.
• [4] Classification of Genes: Standardized Clinical Validity Assessment of Gene-Disease Associations Aids Diagnostic Exome Analysis and Reclassifications. Hum Mutat. 2017 May;38(5):600-608. doi: 10.1002/humu.23183. Epub 2017 Feb 13.
• [5] Hereditary C1q deficiency and systemic lupus erythematosus.QJM. 1994 Aug;87(8):455-64.