- Autoimmunity (HP:0002960): The occurrence of an immune reaction against the organism's own cells or tissues. Evidence: TAS. (OMIM:613652)
- Decreased circulating complement factor I concentration (HP:0005356): Concentration of the complement component factor I in the blood circulation below the lower limit of normal. Evidence: TAS. (OMIM:613652)
- Membranoproliferative glomerulonephritis (HP:0000793): A type of glomerulonephritis characterized by diffuse mesangial cell proliferation and the thickening of capillary walls due to subendothelial extension of the mesangium. The term membranoproliferative glomerulonephritis is often employed to denote a general pattern of glomerular injury seen in a variety of disease processes that share a common pathogenetic mechanism, rather than to describe a single disease entity. Evidence: TAS. Frequency: Occasional (HP:0040283). (OMIM:613652)
- Recurrent infections (HP:0002719): Increased susceptibility to infections as manifested by repeated bouts of infection. Evidence: TAS. (OMIM:613652)
- 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: TAS. (OMIM:613652)
- Systemic lupus erythematosus (HP:0002725): A chronic, relapsing, inflammatory, and often febrile multisystemic disorder of connective tissue, characterized principally by involvement of the skin, joints, kidneys, and serosal membranes. Evidence: TAS. Frequency: Occasional (HP:0040283). (OMIM:613652)
These phenotypes are associated with the disease C1Q deficiency 1 (OMIM:613652).