chrX-154860588-C-A

Variant names:

• chrX-154860588-C-A
• rs137852469
• NM_000132.4:c.6744G>T

Variant summary

Our verdict is Pathogenic. The variant received 6 ACMG points: 6P and 0B. PS4 PP3 PM2_Supporting

This summary comes from the ClinGen Evidence Repository: The NM_000132.3(F8):c.6744G>T (p.Trp2248Cys) is reported in at least 19 patients with mild, moderate or severe hemophilia A in the literature reviewed (PMID:17222201, 18691168, 15921397, 1301932, 17610560). There are several additional probands with the variant reported in the EAHAD database, recorded from the literature and unpublished sources. There are also individuals reported with a history of inhibitor development to factor VIII replacement therapy (EAHAD/CDC Champs Databases). The variant is absent from gnomAD v2.1.1 and v3 meeting PM2_Supporting. This missense variant has a REVEL score of 0.925 (>0.6), meeting criteria for PP3. 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/F9: PS4_Very Strong, PP3, PM2_Supporting. LINK:https://erepo.genome.network/evrepo/ui/classification/CA255218/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:4
• Conservation: PhyloP100: 6.32
• Publications: 4 publications found

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]

F8 Gene-Disease associations (from GenCC):

• hemophilia A

  Inheritance: XL Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen
• mild hemophilia A

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet
• moderately severe hemophilia A

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet
• severe hemophilia A

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet
• symptomatic form of hemophilia A in female carriers

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 6 ACMG points.

• PS4: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PP3: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
F8	NM_000132.4	c.6744G>T	p.Trp2248Cys	missense_variant	Exon 25 of 26	ENST00000360256.9	NP_000123.1
F8	NM_019863.3	c.339G>T	p.Trp113Cys	missense_variant	Exon 4 of 5		NP_063916.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
F8	ENST00000360256.9	c.6744G>T	p.Trp2248Cys	missense_variant	Exon 25 of 26	1	NM_000132.4	ENSP00000353393.4
F8	ENST00000330287.10	c.339G>T	p.Trp113Cys	missense_variant	Exon 4 of 5	1		ENSP00000327895.6
F8	ENST00000644698.1	c.477G>T	p.Trp159Cys	missense_variant	Exon 5 of 6			ENSP00000495706.1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome AF: 9.11e-7 AC: 1 AN: 1097924 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 363280

African (AFR) AF: 0.00 AC: 0 AN: 26393

American (AMR) AF: 0.00 AC: 0 AN: 35206

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 19382

East Asian (EAS) AF: 0.00 AC: 0 AN: 30203

South Asian (SAS) AF: 0.00 AC: 0 AN: 54142

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 40531

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4114

European-Non Finnish (NFE) AF: 0.00000119 AC: 1 AN: 841867

Other (OTH) AF: 0.00 AC: 0 AN: 46086

GnomAD4 genome Cov.: 23

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: reviewed by expert panel

Submissions by phenotype

Hereditary factor VIII deficiency disease Pathogenic:2

Jan 01, 1992

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Feb 02, 2024

ClinGen Coagulation Factor Deficiency Variant Curation Expert Panel, Clingen

Significance: Pathogenic

Review Status: reviewed by expert panel

Collection Method: curation

The NM_000132.3(F8):c.6744G>T (p.Trp2248Cys) is reported in at least 19 patients with mild, moderate or severe hemophilia A in the literature reviewed (PMID: 17222201, 18691168, 15921397, 1301932, 17610560). There are several additional probands with the variant reported in the EAHAD database, recorded from the literature and unpublished sources. There are also individuals reported with a history of inhibitor development to factor VIII replacement therapy (EAHAD/CDC Champs Databases). The variant is absent from gnomAD v2.1.1 and v3 meeting PM2_Supporting. This missense variant has a REVEL score of 0.925 (>0.6), meeting criteria for PP3. 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/F9: PS4_Very Strong, PP3, PM2_Supporting. -

Hereditary factor IX deficiency disease Pathogenic:1

Feb 01, 2019

NIHR Bioresource Rare Diseases, University of Cambridge

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

- -

not provided Pathogenic:1

Oct 07, 2022

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The F8 c.6744G>T; p.Trp2248Cys variant (rs137852469), also known as W2229C in traditional nomenclature, is reported in the literature in multiple individuals affected with mild to severe hemophilia A (Diamond 1992, Markoff 2009, Naylor 1991, see link to FVIII database). This variant is also reported in ClinVar (Variation ID: 10327). This variant is absent from the Genome Aggregation Database, indicating it is not a common polymorphism. The tryptophan at codon 2248 is highly conserved, and computational analyses predict that this variant is deleterious (REVEL: 0.925). Additionally, other variants at this codon (c.6742T>A, p.Trp2248Arg; c.6742T>C, p.Trp2248Arg; c.6743G>C p.Trp2248Ser) have been reported in individuals with mild to severe hemophilia A (Markoff 2009, Santacroce 2008, Shinozawa 2021, Yenchitsomanus 2003). Based on available information, this variant is considered to be pathogenic. References: Link to FVIII database: https://f8-db.eahad.org/index.php Diamond C et al. Amino acid substitutions in conserved domains of factor VIII and related proteins: study of patients with mild and moderately severe hemophilia A. Hum Mutat. 1992;1(3):248-57. PMID: 1301932. 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. PMID: 19473423. Naylor JA et al. Detection of three novel mutations in two haemophilia A patients by rapid screening of whole essential region of factor VIII gene. Lancet. 1991 Mar 16;337(8742):635-9. PMID: 1671991. Santacroce R et al. Identification of 217 unreported mutations in the F8 gene in a group of 1,410 unselected Italian patients with hemophilia A. J Hum Genet. 2008;53(3):275-284. PMID: 18217193. Shinozawa K et al. Spectrum of F8 Genotype and Genetic Impact on Inhibitor Development in Patients with Hemophilia A from Multicenter Cohort Studies (J-HIS) in Japan. Thromb Haemost. 2021 May;121(5):603-615. PMID: 33254277. Yenchitsomanus P et al. Genotype and phenotype of haemophilia A in Thai patients. Haemophilia. 2003 Mar;9(2):179-86. PMID: 12614369. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.71	D
BayesDel_noAF	Pathogenic	0.79
CADD	Pathogenic	28
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.99	.;D;.
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.96	D;D;D
M_CAP	Pathogenic	0.86	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.2	.;H;.
PhyloP100		6.3
PrimateAI	Uncertain	0.62	T
PROVEAN	Pathogenic	-13	D;D;.
REVEL	Pathogenic	0.93
Sift	Pathogenic	0.0	D;D;.
Sift4G	Pathogenic	0.0	D;D;.
Polyphen		1.0	.;D;.
Vest4		0.96
MutPred		0.93		.;Loss of MoRF binding (P = 0.0252);.;
MVP		1.0
MPC		2.4
ClinPred		1.0	D
GERP RS		5.3
Varity_R		1.0
gMVP		1.0
Mutation Taster		=3/97	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs137852469; hg19: chrX-154088863;