6-32027043-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 1P and 0B. PP2

The NM_001002029.4(C4B):c.2513G>A(p.Arg838His) variant causes a missense change. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R838L) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000080 ( 0 hom., cov: 18)

Exomes 𝑓: 0.000012 ( 4 hom. )

Failed GnomAD Quality Control

Consequence

C4B
NM_001002029.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 4.49

Variant links:

Genes affected

C4B (HGNC:1324): (complement C4B (Chido/Rodgers blood group)) This gene encodes the basic form of complement factor 4, and together with the C4A gene, is part of the classical activation pathway. The protein is expressed as a single chain precursor which is proteolytically cleaved into a trimer of alpha, beta, and gamma chains prior to secretion. The trimer provides a surface for interaction between the antigen-antibody complex and other complement components. The alpha chain may be cleaved to release C4 anaphylatoxin, a mediator of local inflammation. Deficiency of this protein is associated with systemic lupus erythematosus. This gene localizes to the major histocompatibility complex (MHC) class III region on chromosome 6. Varying haplotypes of this gene cluster exist, such that individuals may have 1, 2, or 3 copies of this gene. In addition, this gene exists as a long form and a short form due to the presence or absence of a 6.4 kb endogenous HERV-K retrovirus in intron 9. [provided by RefSeq, May 2020]

C4B links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 1 ACMG points.

PP2

Missense variant where missense usually causes diseases, C4B

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
C4B	NM_001002029.4 linkuse as main transcript	c.2513G>A	p.Arg838His	missense_variant	20/41	ENST00000435363.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris
C4B	ENST00000435363.7 linkuse as main transcript	c.2513G>A	p.Arg838His	missense_variant	20/41	1	NM_001002029.4	P1
C4B	ENST00000425700.3 linkuse as main transcript	c.2513G>A	p.Arg838His	missense_variant	20/40	1
C4B	ENST00000647698.1 linkuse as main transcript	c.1220G>A	p.Arg407His	missense_variant	10/31
C4B	ENST00000648821.1 linkuse as main transcript	n.947G>A		non_coding_transcript_exon_variant	8/27

Frequencies

GnomAD3 genomes

AF:

0.00

AC:

AN:

125550

Hom.:

Cov.:

FAILED QC

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000183

Gnomad OTH

AF:

0.00

GnomAD4 exome

Data not reliable, filtered out with message: AS_VQSR

AF:

0.0000122

AC:

AN:

1395016

Hom.:

Cov.:

AF XY:

0.00000864

AC XY:

AN XY:

694126

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000161

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Data not reliable, filtered out with message: AS_VQSR

AF:

0.00000796

AC:

AN:

125550

Hom.:

Cov.:

AF XY:

0.0000166

AC XY:

AN XY:

60150

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000183

Gnomad4 OTH

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 25, 2022

The c.2513G>A (p.R838H) alteration is located in exon 20 (coding exon 20) of the C4B gene. This alteration results from a G to A substitution at nucleotide position 2513, causing the arginine (R) at amino acid position 838 to be replaced by a histidine (H). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.094

BayesDel_addAF

Benign

-0.071

BayesDel_noAF

Benign

-0.34

Cadd

Pathogenic

Dann

Pathogenic

1.0

DEOGEN2

Benign

0.031

T;T

Eigen

Uncertain

0.63

Eigen_PC

Uncertain

0.58

FATHMM_MKL

Uncertain

0.90

M_CAP

Benign

0.018

MetaRNN

Uncertain

0.57

D;D

MetaSVM

Benign

-1.0

MutationAssessor

Uncertain

2.3

M;.

MutationTaster

Benign

1.0

D;D

PROVEAN

Uncertain

-3.4

D;D

REVEL

Benign

0.21

Sift

Uncertain

0.0030

D;D

Sift4G

Pathogenic

0.0

D;D

Polyphen

1.0

.;D

Vest4

0.52

MutPred

0.66

Loss of methylation at R838 (P = 0.019);Loss of methylation at R838 (P = 0.019);

MVP

0.31

ClinPred

0.99

GERP RS

4.5

Varity_R

0.44

gMVP

0.70

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over