rs121909550

Positions:

• chr1-173904007-G-A
• chr1-173904007-G-C

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PS3_Supporting PP1_Strong PP3 PP4 PS4 PM2_Supporting

This summary comes from the ClinGen Evidence Repository: The NM_000488.4(SERPINC1):c.1277C>T variant predicts a missense change from Serine to Leucine at position 426. Several probands and related individuals are reported in the literature with antithrombin deficiency and the Ser426Leu variant, meeting criteria for PS4 and PP4 (multiple publications). The variant was seen across a total of 8 meioses amongst 3 families meeting PP1_Strong (PMID:30721820, 3512602, 3563966). The variant was shown to impair complex formation with thrombin when the variant was expressed in rabbit reticulocytes (PMID:2207328). The variant is absent in gnomAD (v2.1.1 and v3.1.1) meeting PM2_Supporting. It has a REVEL score of 0.88, which meets the PP3 set threshold (>0.6). In summary, this variant meets criteria to be classified as pathogenic. ACMG/AMP criteria applied, as specified by the Thrombosis Variant Curation Expert Panel: PS4, PP1_Strong, PP3, PP4, PS3_Supporting, PM2_Supporting. LINK:https://erepo.genome.network/evrepo/ui/classification/CA210754/MONDO:0013144/084

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SERPINC1 NM_000488.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 9.14

Genes affected

SERPINC1 (HGNC:775): (serpin family C member 1) The protein encoded by this gene, antithrombin III, is a plasma protease inhibitor and a member of the serpin superfamily. This protein inhibits thrombin as well as other activated serine proteases of the coagulation system, and it regulates the blood coagulation cascade. The protein includes two functional domains: the heparin binding-domain at the N-terminus of the mature protein, and the reactive site domain at the C-terminus. The inhibitory activity is enhanced by the presence of heparin. Numerous mutations have been identified for this gene, many of which are known to cause antithrombin-III deficiency which constitutes a strong risk factor for thrombosis. A reduction in the serum level of this protein is associated with severe cases of Coronavirus Disease 19 (COVID-19). [provided by RefSeq, Sep 2020]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SERPINC1	NM_000488.4	c.1277C>T	p.Ser426Leu	missense_variant	7/7	ENST00000367698.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SERPINC1	ENST00000367698.4	c.1277C>T	p.Ser426Leu	missense_variant	7/7	1	NM_000488.4	P1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152164 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

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 AF: 6.84e-7 AC: 1 AN: 1461860 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727236

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 AF: 0.00000657 AC: 1 AN: 152164 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74340

Gnomad4 AFR AF: 0.0000241

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

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary antithrombin deficiency Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	Invitae	Apr 24, 2021	In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Experimental studies have shown that this variant affects SERPINC1 protein function (PMID: 3141397). This variant has been observed in individual(s) with clinical features of antithrombin III deficiency (PMID: 3512602, 2602168, 3563966, 18954896, 20088933, 25298121). It has also been observed to segregate with disease in related individuals. This variant is also known as Milano 2, Denver, and S394L in the literature. ClinVar contains an entry for this variant (Variation ID: 18010). This variant is not present in population databases (ExAC no frequency). This sequence change replaces serine with leucine at codon 426 of the SERPINC1 protein (p.Ser426Leu). The serine residue is highly conserved and there is a large physicochemical difference between serine and leucine. -
Pathogenic, no assertion criteria provided	literature only	OMIM	Apr 06, 1992	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.32
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
CADD	Pathogenic	29
DANN	Pathogenic	1.0
Eigen	Pathogenic	0.91
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.94	D;D
M_CAP	Uncertain	0.16	D
MetaRNN	Pathogenic	0.92	D;D
MetaSVM	Uncertain	0.39	D
MutationTaster	Benign	1.0	A
PrimateAI	Uncertain	0.53	T
Sift4G	Uncertain	0.0060	D;T
Polyphen		1.0	.;D
Vest4		0.95
MVP		0.94
MPC		1.1
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.94
gMVP		0.91

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: rs121909550; hg19: chr1-173873145; COSMIC: COSV62928911; COSMIC: COSV62928911;