chr1-56867662-G-A

Position:

• chr1-56867662-G-A

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_000562.3(C8A):​c.131G>A​(p.Trp44Ter) variant causes a stop gained change. The variant allele was found at a frequency of 0.000000684 in 1,461,630 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 Pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: C8A NM_000562.3 stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 5.49

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]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-56867662-G-A is Pathogenic according to our data. Variant chr1-56867662-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 2102582.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
C8A	NM_000562.3	c.131G>A	p.Trp44Ter	stop_gained	2/11	ENST00000361249.4
C8A	XM_017002234.2	c.131G>A	p.Trp44Ter	stop_gained	2/8
C8A	XM_011542079.3	c.131G>A	p.Trp44Ter	stop_gained	2/8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
C8A	ENST00000361249.4	c.131G>A	p.Trp44Ter	stop_gained	2/11	1	NM_000562.3	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461630 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727122

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 25, 2023

This sequence change creates a premature translational stop signal (p.Trp44*) in the C8A gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in C8A are known to be pathogenic (PMID: 9759902). This variant is not present in population databases (gnomAD no frequency). 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: 2102582). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	45
DANN	Uncertain	1.0
Eigen	Pathogenic	0.87
Eigen_PC	Pathogenic	0.74
FATHMM_MKL	Uncertain	0.91	D
MutationTaster	Benign	1.0	A
Vest4		0.70
GERP RS		5.1

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr1-57333335;