Laboratory for Molecular Diagnostics
Center for Nephrology and Metabolic Disorders

C4b-binding protein beta chain

C4b-binding protein is composed of alpha and beta chains. Three isoforms can be distinguished that constitute 7 alpha and one or none beta or 6 alpha and one beta chains, which are covalently bound by disulfid bridges. Function includes inactivation of activated complement factor 4 in the classical complement activation pathway and binding of coagulation factor protein S. 60% of plasma protein S is non covalently bound to C4b-binding protein. Hence variations of the genes have been associated with various conditions such as thrombophilia, atypical HUS, various infections, immunological type 1 diabetes, and even schizophrenia.

Genetests:

Research Method Carrier testing
Turnaround 5 days
Specimen type genomic DNA
Research Method Genomic sequencing of the entire coding region
Turnaround 25 days
Specimen type genomic DNA

Related Diseases:

Hemolytic-Uremic Syndrome
ADAMTS13
C3
C4BPA
C4BPB
CD46
CFB
CFH
CFHR1
CFHR2
CFHR3
CFHR4
CFHR5
CFI
CLU
DGKE
Methylmalonic aciduria
Methylmalonic aciduria and homocystinuria cblC
MMACHC
Methylmalonic aciduria and homocystinuria cblD
MMADHC
Methylmalonic aciduria type mut
MUT
PIGA
PLG
THBD

References:

1.

Andersson A et al. (1990) Genes for C4b-binding protein alpha- and beta-chains (C4BPA and C4BPB) are located on chromosome 1, band 1q32, in humans and on chromosome 13 in rats.

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2.

Buil A et al. (2010) C4BPB/C4BPA is a new susceptibility locus for venous thrombosis with unknown protein S-independent mechanism: results from genome-wide association and gene expression analyses followed by case-control studies.

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3.

Nonaka MI et al. (2003) Complement C4b-binding protein as a novel murine epididymal secretory protein.

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4.

Törn C et al. (2016) Complement gene variants in relation to autoantibodies to beta cell specific antigens and type 1 diabetes in the TEDDY Study.

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5.

Dahlbäck B et al. (1981) High molecular weight complex in human plasma between vitamin K-dependent protein S and complement component C4b-binding protein.

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6.

Scharfstein J et al. (1978) Human C4-binding protein. I. Isolation and characterization.

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7.

Hillarp A et al. (1990) Cloning of cDNA coding for the beta chain of human complement component C4b-binding protein: sequence homology with the alpha chain.

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8.

Pardo-Manuel F et al. (1990) Human genes for the alpha and beta chains of complement C4b-binding protein are closely linked in a head-to-tail arrangement.

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9.

Hillarp A et al. (1988) Novel subunit in C4b-binding protein required for protein S binding.

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10.

Rodríguez de Córdoba S et al. (1994) The gene coding for the beta-chain of C4b-binding protein (C4BPB) has become a pseudogene in the mouse.

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11.

Hillarp A et al. (1993) The human C4b-binding protein beta-chain gene.

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12.

NCBI article

NCBI 725 [^]
13.

OMIM.ORG article

Omim 120831 [^]
Update: April 29, 2019