chr1-56867686-C-T

Variant names:

Variant summary

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

The NM_000562.3(C8A):c.155C>T(p.Pro52Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000112 in 1,613,656 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. P52P) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000089 ( 0 hom. )

Consequence

C8A
NM_000562.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 1.38

Variant links:

Genes affected

C8A (HGNC:1352): (complement C8 alpha chain) C8 is a component of the complement system and contains three polypeptides, alpha, beta and gamma. This gene encodes the alpha subunit of C8. C8 participates in the formation of the membrane attack complex (MAC). The MAC assembles on bacterial membranes to form a pore, permitting disruption of bacterial membrane organization. Mutations in this gene cause complement C8 alpha-gamma deficiency. [provided by RefSeq, Nov 2008]

C8A 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
C8A	NM_000562.3 link	c.155C>T	p.Pro52Leu	missense_variant	Exon 2 of 11	ENST00000361249.4	NP_000553.1	P07357
C8A	XM_017002234.2 link	c.155C>T	p.Pro52Leu	missense_variant	Exon 2 of 8		XP_016857723.1
C8A	XM_011542079.3 link	c.155C>T	p.Pro52Leu	missense_variant	Exon 2 of 8		XP_011540381.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
C8A	ENST00000361249.4 link	c.155C>T	p.Pro52Leu	missense_variant	Exon 2 of 11	1	NM_000562.3	ENSP00000354458.3		P07357

Frequencies

GnomAD3 genomes

AF:

0.0000329

AC:

AN:

152122

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000724

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000199

AC:

AN:

251024

AF XY:

0.0000147

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000164

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000881

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000890

AC:

AN:

1461416

Hom.:

Cov.:

AF XY:

0.00000688

AC XY:

AN XY:

727034

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33458

American (AMR)

AF:

0.00

AC:

AN:

44664

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26126

East Asian (EAS)

AF:

0.0000504

AC:

AN:

39680

South Asian (SAS)

AF:

0.00

AC:

AN:

86252

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53400

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000810

AC:

AN:

1111708

Other (OTH)

AF:

0.0000166

AC:

AN:

60360

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.463

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.0000328

AC:

AN:

152240

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74424

show subpopulations

African (AFR)

AF:

0.0000722

AC:

AN:

41530

American (AMR)

AF:

0.0000654

AC:

AN:

15290

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000193

AC:

AN:

5182

South Asian (SAS)

AF:

0.00

AC:

AN:

4818

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10610

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68018

Other (OTH)

AF:

0.00

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.535

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00000922

Hom.:

Bravo

AF:

0.0000416

ExAC

AF:

0.0000330

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Feb 15, 2023

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.155C>T (p.P52L) alteration is located in exon 2 (coding exon 2) of the C8A gene. This alteration results from a C to T substitution at nucleotide position 155, causing the proline (P) at amino acid position 52 to be replaced by a leucine (L). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Type I complement component 8 deficiency

Uncertain:1

Mar 12, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Uncertain:1

Jan 06, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces proline, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 52 of the C8A protein (p.Pro52Leu). This variant is present in population databases (rs200247116, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with C8A-related conditions. ClinVar contains an entry for this variant (Variation ID: 1982176). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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

Benign

0.11

BayesDel_addAF

Benign

-0.23

BayesDel_noAF

Benign

-0.34

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.19

Eigen

Uncertain

0.40

Eigen_PC

Uncertain

0.34

FATHMM_MKL

Benign

0.57

LIST_S2

Benign

0.78

M_CAP

Benign

0.021

MetaRNN

Uncertain

0.56

MetaSVM

Benign

-1.0

MutationAssessor

Pathogenic

3.4

PhyloP100

1.4

PrimateAI

Benign

0.36

PROVEAN

Pathogenic

-7.1

REVEL

Benign

0.23

Sift

Uncertain

0.0030

Sift4G

Uncertain

0.0030

Polyphen

1.0

Vest4

0.49

MVP

0.59

MPC

0.22

ClinPred

0.83

GERP RS

4.2

Varity_R

0.72

gMVP

0.46

Mutation Taster

=61/39

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

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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chr1-56867686-C-T

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over