- Discoid lupus rash (HP:0007417): Cutaneous lesion that develops as a dry, scaly, red patch that evolves to an indurated and hyperpigmented plaque with adherent scale. Scarring may result in central white patches (loss of pigmentation) and skin atrophy. Evidence: PCS. Frequency: 4/4. (PMID:17513176;PMID:24160257)
- Recurrent lower respiratory tract infections (HP:0002783): An increased susceptibility to lower respiratory tract infections as manifested by a history of recurrent lower respiratory tract infections. Evidence: PCS. Frequency: 1/3. (PMID:17513176)
- Antinuclear antibody positivity (HP:0003493): The presence of autoantibodies in the serum that react against nuclei or nuclear components. Evidence: PCS. Frequency: 1/3. (PMID:17513176)
- Malar rash (HP:0025300): An erythematous (red), flat facial rash that affects the skin in the malar area (over the cheekbones) and extends over the bridge of the nose. Evidence: PCS. Frequency: 3/3. (PMID:17513176)
- Atelectasis (HP:0100750): Collapse of part of a lung associated with absence of inflation (air) of that part. Evidence: PCS. Frequency: 1/3. (PMID:17513176)
- Childhood onset (HP:0011463): Onset of disease at the age of between 1 and 5 years. Evidence: PCS. Frequency: 4/4. (PMID:17513176;PMID:24160257)
- Anemia (HP:0001903): A reduction in erythrocytes volume or hemoglobin concentration. Evidence: PCS. Frequency: 1/3. (PMID:17513176)
- Sepsis (HP:0100806): Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Evidence: PCS. Frequency: 1/3. (PMID:17513176)
- Pneumocystis jirovecii pneumonia (HP:0020102): An opportunistic disease caused by invasion of unicellular fungus Pneumocystis jirovecii. Transmission of P. jirovecii cysts takes place through the airborne route, and usually, its presence in lungs is asymptomatic. However, people with impaired immunity, especially those with CD4+ T cell count below 200/microliter, are still at risk of the development of Pneumocystis pneumonia due to P. jirovecii invasion. Symptoms induced by this disease are not specific: progressive dyspnea, non-productive cough, low-grade fever, arterial partial pressure of oxygen below 65 mmHg, and chest radiographs demonstrating bilateral, interstitial shadowing. Evidence: PCS. Frequency: 1/3. (PMID:17513176)
- Arthritis (HP:0001369): Inflammation of a joint. Evidence: PCS. Frequency: 1/3. (PMID:17513176)
- Elevated erythrocyte sedimentation rate (HP:0003565): An increased erythrocyte sedimentation rate (ESR). The ESR is a test that measures the distance that erythrocytes have fallen after one hour in a vertical column of anticoagulated blood under the influence of gravity. The ESR is a nonspecific finding. An elevation may indicate inflammation or may be caused by any condition that elevates fibrinogen. Evidence: PCS. Frequency: 1/1. (PMID:24160257)
- Oral ulcer (HP:0000155): Erosion of the mucous mebrane of the mouth with local excavation of the surface, resulting from the sloughing of inflammatory necrotic tissue. Evidence: PCS. Frequency: 1/1. (PMID:24160257)
- Reduced circulating CH50 activity (HP:0025434): A diminished activity of the classical complement pathway as measured by the assay for 50% haemolytic complement (CH50) activity of serum. Evidence: PCS. Frequency: 1/1. (PMID:24160257)
- Facial erythema (HP:0001041): Redness of the skin of the face, caused by hyperemia of the capillaries in the lower layers of the skin. Evidence: PCS. Frequency: 1/1. (PMID:24160257)
- Bronchiectasis (HP:0002110): Persistent abnormal dilatation of the bronchi owing to localized and irreversible destruction and widening of the large airways. Evidence: PCS. Frequency: 1/3. (PMID:17513176)
- Vasculitis in the skin (HP:0200029): A type of vasculitis (inflammation of blood vessel walls) that affects skeletal muscle tissue. Evidence: PCS. Frequency: 1/3. (PMID:17513176)
- Persistent fever (HP:0033399): Fever that persists longer than expected for an acute infectious disease. No precise threshold exists, and the clinical interpretation of fever is context-dependent, but as a rule of thumb, this term refers to fever that persists longer than 2-3 weeks. Evidence: PCS. Frequency: 1/1. (PMID:24160257)
- Extractable nuclear antigen positivity (HP:0033476): The presence of autoantibodies in the serum that react against extractable nuclear components that are referred to as extractable because they can be extracted from cell nuclei with saline solution. Evidence: PCS. Frequency: 1/3. (PMID:17513176)
- Decreased circulating C1q concentration (HP:0034601): Concentration or activity of the C1q protein in the blood circulation below the lower limit of normal. C1q is the first component of the classical pathway and is composed of the C1qA chain, C1qB chain, and C1qC chain, which are encoded by C1qA, C1qB, and C1qC genes. Evidence: PCS. Frequency: 1/1. (PMID:24160257)
- Elevated circulating C-reactive protein concentration (HP:0011227): The concentration of C-reactive protein in the blood circulation is above the upper limit of normal. Evidence: PCS. Frequency: 1/1. (PMID:24160257)
- Anti-Sm antibody positivity (HP:0033040): The presence of autoantibodies in the serum that react to seven proteins that consist of a core of small nuclear ribonucleoprotein (snRNP) particles. Evidence: PCS. Frequency: 1/3. (PMID:17513176)
- Arthralgia (HP:0002829): Joint pain. Evidence: PCS. Frequency: 1/1. (PMID:24160257)
- Autosomal recessive inheritance (HP:0000007): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele). Evidence: PCS. (PMID:24160257)
- Recurrent otitis media (HP:0000403): Increased susceptibility to otitis media, as manifested by recurrent episodes of otitis media. Evidence: PCS. Frequency: 1/3. (PMID:17513176)
- Chilblains (HP:0009710): Chilblains, also called perniosis, are an inflammatory skin condition related to an abnormal vascular response to the cold. We are unaware of a reliable estimate of incidence. It typically presents as tender, pruritic red or bluish lesions located symmetrically on the dorsal aspect of the fingers, toes, ears and nose. Less commonly, reports describe involvement of the thighs and buttocks. The lesions present hours after exposure to cold and usually resolve spontaneously in one to three weeks. Evidence: PCS. Frequency: 1/1. (PMID:24160257)
- Rheumatoid factor positive (HP:0002923): The presence in the serum of an autoantibody directed against the Fc portion of IgG. Evidence: PCS. Frequency: 2/4. (PMID:17513176;PMID:24160257)
These phenotypes are associated with the disease C1Q deficiency 2 (OMIM:620321).