Genetic Variant C8B:p.Arg121Gly (chr1-56956799-G-C) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_000066.4(C8B):c.361C>G(p.Arg121Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,613,792 control chromosomes in the GnomAD database, with no homozygous occurrence. 12/20 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. R121R) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

C8B
NM_000066.4 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 1.36

Publications

6 publications found

Variant links:

Genes affected

C8B (HGNC:1353): (complement C8 beta chain) This gene encodes one of the three subunits of the complement component 8 (C8) protein. C8 is composed of equimolar amounts of alpha, beta and gamma subunits, which are encoded by three separate genes. C8 is one component of the membrane attack complex, which mediates cell lysis, and it initiates membrane penetration of the complex. This protein mediates the interaction of C8 with the C5b-7 membrane attack complex precursor. In humans deficiency of this protein is associated with increased risk of meningococcal infections. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jun 2013]

C8B Gene-Disease associations (from GenCC):

type II complement component 8 deficiency
Inheritance: AR Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)

C8B links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
C8B	NM_000066.4 link	c.361C>G	p.Arg121Gly	missense_variant	Exon 3 of 12	ENST00000371237.9	NP_000057.3	P07358
C8B	NM_001278543.2 link	c.205C>G	p.Arg69Gly	missense_variant	Exon 4 of 13		NP_001265472.2	B7Z555
C8B	NM_001278544.2 link	c.175C>G	p.Arg59Gly	missense_variant	Exon 4 of 13		NP_001265473.2	B7Z550
C8B	XM_047429957.1 link	c.361C>G	p.Arg121Gly	missense_variant	Exon 3 of 7		XP_047285913.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
C8B	ENST00000371237.9 link	c.361C>G	p.Arg121Gly	missense_variant	Exon 3 of 12	1	NM_000066.4	ENSP00000360281.4		P07358

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

152002

Hom.:

Cov.:

show subpopulations

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000274

AC:

AN:

1461790

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727210

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33474

American (AMR)

AF:

0.00

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53404

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000360

AC:

AN:

1111942

Other (OTH)

AF:

0.00

AC:

AN:

60390

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.00000658

AC:

AN:

152002

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74226

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41396

American (AMR)

AF:

0.00

AC:

AN:

15262

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5148

South Asian (SAS)

AF:

0.00

AC:

AN:

4814

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10576

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68022

Other (OTH)

AF:

0.00

AC:

AN:

2088

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.13

BayesDel_addAF

Benign

-0.15

BayesDel_noAF

Benign

-0.45

CADD

Benign

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.028

.;T;.

Eigen

Benign

-0.12

Eigen_PC

Benign

-0.011

FATHMM_MKL

Benign

0.33

LIST_S2

Uncertain

0.88

.;D;D

M_CAP

Benign

0.0072

MetaRNN

Uncertain

0.51

D;D;D

MetaSVM

Benign

-1.1

PhyloP100

1.4

PrimateAI

Benign

0.40

PROVEAN

Uncertain

-2.6

D;N;N

REVEL

Benign

0.18

Sift

Benign

0.15

T;T;T

Sift4G

Benign

0.40

T;T;T

Polyphen

0.98, 0.65

.;D;P

Vest4

0.54

MutPred

0.67

Loss of MoRF binding (P = 0.082);.;.;

MVP

0.55

MPC

0.13

ClinPred

0.83

GERP RS

5.4

gMVP

0.63

Mutation Taster

=82/18

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.12

Details are displayed if max score is > 0.2

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

Publications

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1-56956799-G-C

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over