Late complement pathway defects

C5 deficiency
C6 deficiency
C7 deficiency
C8 deficiency
C9 deficiency

Late complement component (the final common pathway C5b-C9 components) deficiencies are all inherited in an autosomal recessive manner. In all cases, homozygous recessive patients have greatly reduced levels of the respective complement component. Generally, patients with deficiencies of C5, C6, C7, or C8 are particularly susceptible to systemic infections with Neisseria meningitidies and N. gonorrhoeae. Infections are rarely fulminant but are often recurrent and frequently involve unusual serotypes of the organism.

Primary immunodeficiency

C5 [HSA:727] [KO:K03994]
C6 [HSA:729] [KO:K03995]
C7 [HSA:730] [KO:K03996]
C8 alpha [HSA:731] [KO:K03997]
C8 beta [HSA:732] [KO:K03998]
C8 gamma [HSA:733] [KO:K03999]
C9 [HSA:735] [KO:K04000]

PMID:19758139

Pettigrew HD, Teuber SS, Gershwin ME

Clinical significance of complement deficiencies.

Ann N Y Acad Sci 1173:108-23 (2009)
DOI:10.1111/j.1749-6632.2009.04633.x

PMID:17162365

Kumar A, Teuber SS, Gershwin ME.

Current perspectives on primary immunodeficiency diseases.

Clin Dev Immunol 13:223-59 (2006)
DOI:10.1080/17402520600800705

PMID:17952897

Geha RS, Notarangelo LD, Casanova JL, Chapel H, Conley ME, Fischer A, Hammarstrom L, Nonoyama S, Ochs HD, Puck JM, Roifman C, Seger R, Wedgwood J.

Primary immunodeficiency diseases: an update from the International Union of Immunological Societies Primary Immunodeficiency Diseases Classification Committee.

J Allergy Clin Immunol 120:776-94 (2007)
DOI:10.1016/j.jaci.2007.08.053