rs138963205

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2PP3_Strong

The NM_001768.7(CD8A):​c.656G>T​(p.Arg219Leu) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000887 in 1,612,478 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. 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. R219W) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000059 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000092 ( 0 hom. )

Consequence

CD8A
NM_001768.7 missense, splice_region

Scores

7
10
2
Splicing: ADA: 0.9999
2

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 3.31

Publications

5 publications found
Variant links:
Genes affected
CD8A (HGNC:1706): (CD8 subunit alpha) The CD8 antigen is a cell surface glycoprotein found on most cytotoxic T lymphocytes that mediates efficient cell-cell interactions within the immune system. The CD8 antigen acts as a coreceptor with the T-cell receptor on the T lymphocyte to recognize antigens displayed by an antigen presenting cell in the context of class I MHC molecules. The coreceptor functions as either a homodimer composed of two alpha chains or as a heterodimer composed of one alpha and one beta chain. Both alpha and beta chains share significant homology to immunoglobulin variable light chains. This gene encodes the CD8 alpha chain. Multiple transcript variants encoding different isoforms have been found for this gene. The major protein isoforms of this gene differ by the presence or absence of a transmembrane domain and thus differ in being a membrane-anchored or secreted protein. [provided by RefSeq, May 2020]
CD8A Gene-Disease associations (from GenCC):
  • susceptibility to respiratory infections associated with CD8alpha chain mutation
    Inheritance: AR Classification: STRONG, SUPPORTIVE, LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), Orphanet, ClinGen

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
PP3
Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
CD8ANM_001768.7 linkc.656G>T p.Arg219Leu missense_variant, splice_region_variant Exon 5 of 6 ENST00000283635.8 NP_001759.3 P01732-1Q6ZVS2Q8TAW8

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
CD8AENST00000283635.8 linkc.656G>T p.Arg219Leu missense_variant, splice_region_variant Exon 5 of 6 1 NM_001768.7 ENSP00000283635.3 P01732-1

Frequencies

GnomAD3 genomes
AF:
0.0000593
AC:
9
AN:
151792
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.0000485
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:
0.0000240
AC:
6
AN:
250504
AF XY:
0.0000369
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000529
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000917
AC:
134
AN:
1460686
Hom.:
0
Cov.:
31
AF XY:
0.0000757
AC XY:
55
AN XY:
726604
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33438
American (AMR)
AF:
0.00
AC:
0
AN:
44648
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26120
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39690
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86008
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53408
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.000110
AC:
122
AN:
1111246
Other (OTH)
AF:
0.000199
AC:
12
AN:
60360
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.467
Heterozygous variant carriers
0
6
12
18
24
30
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
10
20
30
40
50
<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:
0.0000593
AC:
9
AN:
151792
Hom.:
0
Cov.:
32
AF XY:
0.0000675
AC XY:
5
AN XY:
74088
show subpopulations
African (AFR)
AF:
0.0000485
AC:
2
AN:
41278
American (AMR)
AF:
0.00
AC:
0
AN:
15254
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5174
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4804
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10530
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.000103
AC:
7
AN:
67970
Other (OTH)
AF:
0.00
AC:
0
AN:
2084
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
Heterozygous variant carriers
0
1
2
2
3
4
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:
0.0000813
Hom.:
0
Bravo
AF:
0.0000491
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000465
AC:
4
ExAC
AF:
0.0000412
AC:
5
EpiCase
AF:
0.000164
EpiControl
AF:
0.00

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Susceptibility to respiratory infections associated with CD8alpha chain mutation Uncertain:1
Aug 26, 2021
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces arginine with leucine at codon 219 of the CD8A protein (p.Arg219Leu). The arginine residue is highly conserved and there is a moderate physicochemical difference between arginine and leucine. This variant also falls at the last nucleotide of exon 5, which is part of the consensus splice site for this exon. This variant is present in population databases (rs138963205, ExAC 0.008%). This variant has not been reported in the literature in individuals affected with CD8A-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Uncertain
0.39
BayesDel_addAF
Uncertain
0.13
D
BayesDel_noAF
Uncertain
0.070
CADD
Pathogenic
36
DANN
Uncertain
1.0
DEOGEN2
Pathogenic
0.85
.;D;D;T
Eigen
Pathogenic
0.72
Eigen_PC
Uncertain
0.66
FATHMM_MKL
Uncertain
0.87
D
LIST_S2
Benign
0.77
T;.;D;D
M_CAP
Uncertain
0.22
D
MetaRNN
Pathogenic
0.85
D;D;D;D
MetaSVM
Uncertain
0.66
D
MutationAssessor
Pathogenic
3.0
.;M;M;.
PhyloP100
3.3
PrimateAI
Uncertain
0.62
T
PROVEAN
Uncertain
-3.9
D;D;D;D
REVEL
Pathogenic
0.65
Sift
Pathogenic
0.0
D;D;D;D
Sift4G
Pathogenic
0.0
D;D;D;D
Polyphen
1.0
D;D;D;.
Vest4
0.79
MVP
0.95
MPC
1.7
ClinPred
1.0
D
GERP RS
5.0
Varity_R
0.77
gMVP
0.41
Mutation Taster
=50/50

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
1.0
dbscSNV1_RF
Pathogenic
0.93
SpliceAI score (max)
0.20
Details are displayed if max score is > 0.2
DS_DL_spliceai
0.20
Position offset: 0

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

Publications

Other links and lift over

dbSNP: rs138963205; hg19: chr2-87015653; API