Laboratory for Molecular Diagnostics
Center for Nephrology and Metabolic Disorders

Complement C9 deficiency

Complement component 9 deficiency is caused by mutations of the C9 gene. If both alleles are altered C9 is undetectable in plasma. No liability to any specific disease is observed in such a condition. The clinical manifestations seem to be tempered in paroxysmal nocturnal hemoglobinuria with complement component 9 deficiency.


C9 deficiency has a frequency of about 2/1000 in Japan.[Error: Macro 'ref' doesn't exist]


Hereditary complement disorders
CR1 deficiency
Complement C2 deficiency
Complement C3 deficiency
Complement C5 deficiency
Complement C6 deficiency
Complement C7 deficiency
Complement C8 deficiency
Complement C9 deficiency
Complement component C4 deficiency
Complement factor D deficiency
Complement factor I deficiency
Early pathway complement deficiencies
Hereditary Angioedema
Properdin deficiency, X-linked
Terminal pathway complement deficiencies
Thrombotic microangiopathies



Ichikawa E et al. (2001) Hereditary complement (C9) deficiency associated with dermatomyositis.


Zoppi M et al. (1990) Recurrent meningitis in a patient with congenital deficiency of the C9 component of complement. First case of C9 deficiency in Europe.


Abbott C et al. (1989) The gene for human complement component C9 mapped to chromosome 5 by polymerase chain reaction.


Witzel-Schlömp K et al. (1997) The human complement C9 gene: identification of two mutations causing deficiency and revision of the gene structure.


Hobart MJ et al. (1997) Difficulties in the ascertainment of C9 deficiency: lessons to be drawn from a compound heterozygote C9-deficient subject.


Horiuchi T et al. (1998) A non-sense mutation at Arg95 is predominant in complement 9 deficiency in Japanese.


Witzel-Schlömp K et al. (1998) Heterogeneity in the genetic basis of human complement C9 deficiency.


Alvarez V et al. (1995) Genetic detection of the silent allele (*Q0) in hereditary deficiencies of the human complement C6, C7, and C9 components.


Fukumori Y et al. (1998) Terminal complement component deficiencies in Japan.


Kira R et al. (1999) Molecular epidemiology of C9 deficiency heterozygotes with an Arg95Stop mutation of the C9 gene in Japan.


Yonemura Y et al. (1990) Paroxysmal nocturnal haemoglobinuria with coexisting deficiency of the ninth component of complement: lack of massive haemolytic attack.


Nagata M et al. (1989) Inherited deficiency of ninth component of complement: an increased risk of meningococcal meningitis.


Lint TF et al. (1980) Inherited deficiency of the ninth component of complement in man.


OMIM.ORG article

Omim 613825 [^]
Update: May 9, 2019