rs150022116

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PVS1PP5

The NM_000066.4(C8B):​c.361C>T​(p.Arg121*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000929 in 1,613,906 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. R121R) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000098 ( 0 hom. )

Consequence

C8B
NM_000066.4 stop_gained

Scores

3
2
2

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3U:1

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)

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

PVS1
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PP5
Variant 1-56956799-G-A is Pathogenic according to our data. Variant chr1-56956799-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 35593.We mark this variant Likely_pathogenic, oryginal submission is: [Conflicting_classifications_of_pathogenicity].

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
C8BNM_000066.4 linkc.361C>T p.Arg121* stop_gained Exon 3 of 12 ENST00000371237.9 NP_000057.3 P07358
C8BNM_001278543.2 linkc.205C>T p.Arg69* stop_gained Exon 4 of 13 NP_001265472.2 B7Z555
C8BNM_001278544.2 linkc.175C>T p.Arg59* stop_gained Exon 4 of 13 NP_001265473.2 B7Z550
C8BXM_047429957.1 linkc.361C>T p.Arg121* stop_gained Exon 3 of 7 XP_047285913.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
C8BENST00000371237.9 linkc.361C>T p.Arg121* stop_gained Exon 3 of 12 1 NM_000066.4 ENSP00000360281.4 P07358

Frequencies

GnomAD3 genomes
AF:
0.0000461
AC:
7
AN:
152000
Hom.:
0
Cov.:
32
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:
0.000103
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.000135
AC:
34
AN:
251312
AF XY:
0.000118
show subpopulations
Gnomad AFR exome
AF:
0.0000615
Gnomad AMR exome
AF:
0.0000578
Gnomad ASJ exome
AF:
0.000794
Gnomad EAS exome
AF:
0.0000544
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.000185
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000978
AC:
143
AN:
1461788
Hom.:
0
Cov.:
30
AF XY:
0.000102
AC XY:
74
AN XY:
727208
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33474
American (AMR)
AF:
0.0000671
AC:
3
AN:
44720
Ashkenazi Jewish (ASJ)
AF:
0.000421
AC:
11
AN:
26134
East Asian (EAS)
AF:
0.0000252
AC:
1
AN:
39700
South Asian (SAS)
AF:
0.0000464
AC:
4
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53404
Middle Eastern (MID)
AF:
0.00104
AC:
6
AN:
5768
European-Non Finnish (NFE)
AF:
0.0000998
AC:
111
AN:
1111940
Other (OTH)
AF:
0.000116
AC:
7
AN:
60390
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.499
Heterozygous variant carriers
0
10
21
31
42
52
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
4
8
12
16
20
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.0000460
AC:
7
AN:
152118
Hom.:
0
Cov.:
32
AF XY:
0.0000538
AC XY:
4
AN XY:
74352
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41518
American (AMR)
AF:
0.00
AC:
0
AN:
15282
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5136
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4810
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10576
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
292
European-Non Finnish (NFE)
AF:
0.000103
AC:
7
AN:
68014
Other (OTH)
AF:
0.00
AC:
0
AN:
2110
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.504
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.000224
Hom.:
1
Bravo
AF:
0.0000718
ExAC
AF:
0.000107
AC:
13
EpiCase
AF:
0.000164
EpiControl
AF:
0.000178

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:3Uncertain:1
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Type II complement component 8 deficiency Pathogenic:2
Sep 01, 2009
OMIM
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:literature only

- -

Feb 15, 2024
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Variant summary: C8B c.361C>T (p.Arg121X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. The variant allele was found at a frequency of 0.00014 in 251312 control chromosomes (gnomAD). c.361C>T (also known as 388C>T) has been reported in the literature in multiple individuals affected with Type II Complement Component 8 Deficiency (examples: Saucedo_1995, Sissy_2019). The following publications have been ascertained in the context of this evaluation (PMID: 31440263, 7594510). These data indicate that the variant is very likely to be associated with disease. ClinVar contains an entry for this variant (Variation ID: 35593). Based on the evidence outlined above, the variant was classified as pathogenic. -

not provided Pathogenic:1
Nov 04, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Arg121*) in the C8B gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in C8B are known to be pathogenic (PMID: 7594510). This variant is present in population databases (rs150022116, gnomAD 0.09%). This premature translational stop signal has been observed in individual(s) with C8B-related conditions (PMID: 7594510, 31440263). This variant is also known as 388C>T. ClinVar contains an entry for this variant (Variation ID: 35593). For these reasons, this variant has been classified as Pathogenic. -

not specified Uncertain:1
May 03, 2020
Genomic Research Center, Shahid Beheshti University of Medical Sciences
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.44
D
BayesDel_noAF
Pathogenic
0.60
CADD
Pathogenic
38
DANN
Uncertain
1.0
Eigen
Pathogenic
0.69
Eigen_PC
Uncertain
0.51
FATHMM_MKL
Benign
0.29
N
PhyloP100
1.4
Vest4
0.90
GERP RS
5.4
Mutation Taster
=0/200
disease causing (fs/PTC)

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.13
Details are displayed if max score is > 0.2

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

Publications

Other links and lift over

dbSNP: rs150022116; hg19: chr1-57422472; COSMIC: COSV64776847; COSMIC: COSV64776847; API