1-22661354-G-T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2 PM5 PP3_Strong

The NM_001378156.1(C1QB):c.724G>T(p.Gly242Trp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000658 in 151,944 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G242R) has been classified as Pathogenic.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 31)
• Consequence: C1QB NM_001378156.1 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.63

Genes affected

C1QB (HGNC:1242): (complement C1q B chain) This gene encodes the B-chain polypeptide of serum complement subcomponent C1q, which associates with C1r and C1s to yield the first component of the serum complement system. C1q is composed of 18 polypeptide chains which include 6 A-chains, 6 B-chains, and 6 C-chains. Each chain contains an N-terminal collagen-like region and a C-terminal C1q globular domain. C1q deficiency is associated with lupus erythematosus and glomerulonephritis. [provided by RefSeq, Dec 2016]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-22661354-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 440742.Status of the report is no_assertion_criteria_provided, 0 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.989

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
C1QB	NM_001378156.1	c.724G>T	p.Gly242Trp	missense_variant	3/3	ENST00000509305.6
C1QB	NM_000491.5	c.730G>T	p.Gly244Trp	missense_variant	3/3
C1QB	NM_001371184.3	c.724G>T	p.Gly242Trp	missense_variant	4/4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
C1QB	ENST00000509305.6	c.724G>T	p.Gly242Trp	missense_variant	3/3	1	NM_001378156.1	P2

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 151944 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.0000242

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: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 32

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 151944 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 74190

Gnomad4 AFR AF: 0.0000242

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.56
Cadd	Pathogenic	32
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.65	D;D
Eigen	Pathogenic	0.95
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.91	D;D
M_CAP	Pathogenic	0.57	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	1.1	D
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.68	T
PROVEAN	Pathogenic	-7.5	D;D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	.;D
Vest4		0.96
MutPred		0.91		.;Loss of sheet (P = 0.0457);
MVP		0.98
MPC		1.5
ClinPred		1.0	D
GERP RS		5.2
Varity_R		0.96
gMVP		0.90

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

LitVar

Other links and lift over

dbSNP: rs34813378; hg19: chr1-22987847;