rs137852453

Positions:

• chrX-154902120-G-A

Variant summary

Our verdict is Pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2_Supporting PS4 PP4_Moderate PP3

This summary comes from the ClinGen Evidence Repository: The c.6046C>T (p.Arg2016Trp) variant is completely absent from gnomAD v2.1.1 and gnomAD v3 meeting PM2_Supporting. This missense variant has a REVEL score of 0.822 (>0.6) meeting PP3 criteria. More than 46 probands are reported with the variant and moderate-severe hemophilia A in the literature and internal laboratory data (PMID:29296726, 20102490, 18387975), meeting F8 phenotype criteria. This variant has been associated with discrepant factor VIII activity levels (PMID:32232366). This variant has also been reported in individuals with a history of inhibitor development to factor replacement therapy (EAHAD database). In summary, this variant meets criteria to be classified as pathogenic. ACMG/AMP criteria applied, as specified by the Coagulation Factor Deficiency Variant Curation Expert Panel for F8: PS4_Very Strong, PP4_Moderate, PP3, PM2_Supporting. LINK:https://erepo.genome.network/evrepo/ui/classification/CA255197/MONDO:0010602/071

• Frequency:
  • Genomes: not found (cov: 23)
  • Exomes 𝑓: 9.1e-7 (0 hom. 0 hem.)
• Consequence: F8 NM_000132.4 missense
• Clinical Significance: Pathogenic reviewed by expert panel P:5
• Conservation: PhyloP100: 1.40

Genes affected

F8 (HGNC:3546): (coagulation factor VIII) This gene encodes coagulation factor VIII, which participates in the intrinsic pathway of blood coagulation; factor VIII is a cofactor for factor IXa which, in the presence of Ca+2 and phospholipids, converts factor X to the activated form Xa. This gene produces two alternatively spliced transcripts. Transcript variant 1 encodes a large glycoprotein, isoform a, which circulates in plasma and associates with von Willebrand factor in a noncovalent complex. This protein undergoes multiple cleavage events. Transcript variant 2 encodes a putative small protein, isoform b, which consists primarily of the phospholipid binding domain of factor VIIIc. This binding domain is essential for coagulant activity. Defects in this gene results in hemophilia A, a common recessive X-linked coagulation disorder. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 8 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
F8	NM_000132.4	c.6046C>T	p.Arg2016Trp	missense_variant	19/26	ENST00000360256.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
F8	ENST00000360256.9	c.6046C>T	p.Arg2016Trp	missense_variant	19/26	1	NM_000132.4	P1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome AF: 9.12e-7 AC: 1 AN: 1096647 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 362067

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: 0.00000119

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 23

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: reviewed by expert panel

Submissions by phenotype

Hereditary factor VIII deficiency disease Pathogenic:5

Pathogenic, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	Jul 22, 2018	The F8 c.6046C>T; p.Arg2016Trp variant (rs137852453), also known as p.Arg1997Trp in traditional nomenclature, is reported in the literature in multiple individuals and families affected with severe to moderate/mild hemophilia A (Fernandez-Lopez 2005, Garagiola 2015, Guo 2018, Higuchi 1991, Hill 2005, Liu 1998, Pieneman 1995, Reitter 2010, Rossetti 2007, Santagostino 2010, Theophilus 2001, Timur 2001, Vidal 2001, Waseem 1999). This variant is absent from general population databases (1000 Genomes Project, Exome Variant Server, and Genome Aggregation Database), indicating it is not a common polymorphism. Additionally, multiple other variants at this codon (p.Arg2016Gln/Leu/Pro) have been reported in individuals with hemophilia A (Markoff 2009, Vidal 2001). Functional analyses of the variant protein show a reduction in secreted protein and activity, and an impact on splicing that further reduces protein activity (Donadon 2018, Theophilus 2001). The arginine at codon 2016 is highly conserved, and computational analyses (SIFT, PolyPhen-2) predict that this variant is deleterious. Based on available information, this variant is considered to be pathogenic. References: Donadon I et al. Clustered F8 missense mutations cause hemophilia A by combined alteration of splicing and protein biosynthesis and activity. Haematologica. 2018 Feb;103(2):344-350. Fernandez-Lopez O et al. The spectrum of mutations in Southern Spanish patients with hemophilia A and identification of 28 novel mutations. Haematologica. 2005 May;90(5):707-10. Garagiola I et al. A recurrent F8 mutation (c.6046C>T) causing hemophilia A in 8% of northern Italian patients: evidence for a founder effect. Mol Genet Genomic Med. 2015 Dec 14;4(2):152-9. Guo Z et al. Spectrum of Molecular Defects in 216 Chinese Families With Hemophilia A: Identification of Noninversion Mutation Hot Spots and 42 Novel Mutations. Clin Appl Thromb Hemost. 2018 Jan;24(1):70-78. Higuchi M et al. Molecular characterization of mild-to-moderate hemophilia A: detection of the mutation in 25 of 29 patients by denaturing gradient gel electrophoresis. Proc Natl Acad Sci U S A. 1991 Oct 1;88(19):8307-11. Hill M et al. Mutation analysis in 51 patients with haemophilia A: report of 10 novel mutations and correlations between genotype and clinical phenotype. Haemophilia. 2005 Mar;11(2):133-41. Liu M et al. A domain mutations in 65 haemophilia A families and molecular modelling of dysfunctional factor VIII proteins. Br J Haematol. 1998 Dec;103(4):1051-60. Markoff A et al. Combined homology modelling and evolutionary significance evaluation of missense mutations in blood clotting factor VIII to highlight aspects of structure and function. Haemophilia. 2009 Jul;15(4):932-41. Pieneman WC et al. Screening for mutations in haemophilia A patients by multiplex PCR-SSCP, Southern blotting and RNA analysis: the detection of a genetic abnormality in the factor VIII gene in 30 out of 35 patients. Br J Haematol. 1995 Jun;90(2):442-9. Reitter S et al. Spectrum of causative mutations in patients with haemophilia A in Austria. Thromb Haemost. 2010 Jul;104(1):78-85. Rossetti LC et al. Sixteen novel hemophilia A causative mutations in the first Argentinian series of severe molecular defects. Haematologica. 2007 Jun;92(6):842-5. Santagostino E et al. Severe hemophilia with mild bleeding phenotype: molecular characterization and global coagulation profile. J Thromb Haemost. 2010 Apr;8(4):737-43. Theophilus BD et al. Site and type of mutations in the factor VIII gene in patients and carriers of haemophilia A. Haemophilia. 2001 Jul;7(4):381-91. Timur AA et al. Molecular pathology of haemophilia A in Turkish patients: identification of 36 independent mutations. Haemophilia. 2001 Sep;7(5):475-81. Vidal F et al. Rapid hemophilia A molecular diagnosis by a simple DNA sequencing procedure: identification of 14 novel mutations. Thromb Haemost. 2001 Apr;85(4):580-3. Waseem NH et al. Start of UK confidential haemophilia A database: analysis -
Pathogenic, no assertion criteria provided	literature only	OMIM	Jan 01, 1995	- -
Pathogenic, reviewed by expert panel	curation	ClinGen Coagulation Factor Deficiency Variant Curation Expert Panel, Clingen	Feb 02, 2024	The c.6046C>T (p.Arg2016Trp) variant is completely absent from gnomAD v2.1.1 and gnomAD v3 meeting PM2_Supporting. This missense variant has a REVEL score of 0.822 (>0.6) meeting PP3 criteria. More than 46 probands are reported with the variant and moderate-severe hemophilia A in the literature and internal laboratory data (PMID: 29296726, 20102490, 18387975), meeting F8 phenotype criteria. This variant has been associated with discrepant factor VIII activity levels (PMID: 32232366). This variant has also been reported in individuals with a history of inhibitor development to factor replacement therapy (EAHAD database). In summary, this variant meets criteria to be classified as pathogenic. ACMG/AMP criteria applied, as specified by the Coagulation Factor Deficiency Variant Curation Expert Panel for F8: PS4_Very Strong, PP4_Moderate, PP3, PM2_Supporting. -
Pathogenic, no assertion criteria provided	clinical testing	Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione IRCCS Ca Granda Ospedale Maggiore Policlinico	Jun 01, 2019	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genetics and Molecular Pathology, SA Pathology	Oct 01, 2020	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.42
BayesDel_addAF	Pathogenic	0.48	D
BayesDel_noAF	Pathogenic	0.45
CADD	Benign	23
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.99	D
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.91	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Benign	2.0	M
MutationTaster	Benign	0.99	D
PrimateAI	Benign	0.48	T
PROVEAN	Uncertain	-3.5	D
REVEL	Pathogenic	0.82
Sift	Benign	0.082	T
Sift4G	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		0.87
MutPred		0.93		Loss of sheet (P = 0.0228);
MVP		1.0
MPC		2.0
ClinPred		0.99	D
GERP RS		3.3
Varity_R		0.81
gMVP		0.99

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.17		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: rs137852453; hg19: chrX-154130395; COSMIC: COSV64270541; COSMIC: COSV64270541;