1-173904027-AG-TC

Variant names:

• chr1-173904027-AG-TC
• NM_000488.4:c.1256_1257delCTinsGA
• SERPINC1 p.Ala419Gly

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM1 PP2

The NM_000488.4(SERPINC1):​c.1256_1257delCTinsGA​(p.Ala419Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. 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. A419V) has been classified as Uncertain significance. The gene SERPINC1 is included in the ClinGen Criteria Specification Registry.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SERPINC1 NM_000488.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.0430
• Publications: 0 publications found

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]

SERPINC1 Gene-Disease associations (from GenCC):

• hereditary antithrombin deficiency

  Inheritance: AD, AR, SD Classification: DEFINITIVE, STRONG, SUPPORTIVE, LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), PanelApp Australia, Genomics England PanelApp, Orphanet, ClinGen

ACMG classification

Specifications for SERPINC1 are available in the ClinGen Criteria Specification Registry and recommended for reference when assigning criteria.

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_000488.4
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 59 curated pathogenic missense variants (we use a threshold of 10). The gene has 8 curated benign missense variants. Gene score misZ: 1.3587 (below the threshold of 3.09). Trascript score misZ: 2.7609 (below the threshold of 3.09). GenCC associations: The gene is linked to hereditary antithrombin deficiency.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000488.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SERPINC1	NM_000488.4	MANE Select	c.1256_1257delCTinsGA	p.Ala419Gly	missense	N/A	NP_000479.1	P01008
	SERPINC1	NM_001386302.1		c.1379_1380delCTinsGA	p.Ala460Gly	missense	N/A	NP_001373231.1
	SERPINC1	NM_001386303.1		c.1337_1338delCTinsGA	p.Ala446Gly	missense	N/A	NP_001373232.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SERPINC1	ENST00000367698.4	TSL:1 MANE Select	c.1256_1257delCTinsGA	p.Ala419Gly	missense	N/A	ENSP00000356671.3	P01008
	SERPINC1	ENST00000874328.1		c.1385_1386delCTinsGA	p.Ala462Gly	missense	N/A	ENSP00000544387.1
	SERPINC1	ENST00000874324.1		c.1379_1380delCTinsGA	p.Ala460Gly	missense	N/A	ENSP00000544383.1

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		0.043

Splicing

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr1-173873165;