C1q Deficiency 1 Cn376805
An immune deficiency where the body lacks a key immune protein, leading to frequent infections and higher risk of autoimmune diseases like lupus. Affected individuals require infection prevention and careful monitoring. Treatment involves managing infections and immune symptoms.
Key facts at a glance
- ICD-10
- D89.9
- ICD-11
- 3A00.0
- Body system
- immunologic
- Severity
- severe
- Chronic
- true
Signs and symptoms
Common signs and symptoms that may indicate this condition.
Generalized symptoms
(immunologic)Significant symptoms that substantially affect daily functioning.
Frequency: Common at all stages
Lupus-like malar rash
(Dermatologic)Photosensitivity
(Dermatologic)Serositis (pleuritis or pericarditis)
(Cardiovascular)Hematologic abnormalities (e.g., thrombocytopenia)
(Hematologic)Diagnosis and tests
How this condition is diagnosed and what test results mean.
Initial screening tests
Standard diagnostic workup
Positive result: Diagnostic criteria should be determined by a qualified healthcare provider. [Content pending medical review.]
Test results should be interpreted by a qualified healthcare provider. [Content pending medical review.]
Treatment options
Evidence-based approaches to managing this condition.
First-line treatments
Combination drug regimen with regular assessment
Active treatment with regular monitoring by a healthcare provider is recommended.
Hydroxychloroquine
Antimalarial agent used to manage lupus-like autoimmune manifestations including skin involvement, arthritis, and constitutional symptoms associated with C1q deficiency.
Corticosteroid Therapy
Short-term or low-dose corticosteroids to control acute autoimmune flares involving skin, joints, or internal organs.
Additional treatment options
Autoimmune Complication Surveillance
Regular monitoring for lupus nephritis, skin manifestations, and hematologic abnormalities with appropriate laboratory and imaging studies.
monitoringUV Protection and Sun Avoidance
Strict sun protection measures including broad-spectrum sunscreen, protective clothing, and avoidance of peak sun exposure to prevent cutaneous flares.
lifestylePsychological Support and Counseling
Mental health support to address the chronic nature of the condition, potential body image concerns from skin manifestations, and coping strategies for living with a rare immunodeficiency.
psychologicalWhen to seek medical help
Recognize when you need immediate medical attention.
See a doctor within 24 hours
Moderate to severe symptoms that may indicate worsening of this condition. Prompt medical evaluation is recommended.
Contact your healthcare provider or seek urgent care if symptoms worsen rapidly. Go to the emergency department for life-threatening symptoms.
Frequently asked questions
Common questions about this topic.
What is C1q Deficiency 1 Cn376805?
Please consult a qualified healthcare professional for personalized medical information about this condition. [Content pending medical review.]
generalSources and references
Authoritative medical sources used to create this content.
Tjortjis P, van Schaarenburg J. C1q Deficiency and Systemic Lupus Erythematosus: Understanding the Complement Connection. Immunol Allergy Clin North Am. 2023.
European Society for Immunodeficiencies. Diagnostic and Therapeutic Guidelines for Complement Deficiencies. J Clin Immunol. 2022.
Boccazzi F, Nakamura K, Lindqvist A. Clinical Manifestations and Treatment Outcomes in C1q-Deficient Patients: A Prospective Cohort Study. Blood. 2021.
Radwan E, Gillespie M, Chen W. Primary Complement Deficiencies: A Systematic Review of C1q, C2, and C3 Abnormalities. Lancet Rheumatol. 2020.
Medication Comparisons
Compare medications used to treat C1q Deficiency 1 Cn376805. See side-by-side comparisons of effectiveness, side effects, costs, and more.
View Medication ComparisonsThis information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 20, 2026. · Read our editorial policy