rs137852249

Positions:

• chrX-139561566-G-A
• chrX-139561566-G-T

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PP1 PM2_Supporting PP4_Moderate PM1 PS3_Supporting PS4

This summary comes from the ClinGen Evidence Repository: The c.881G>A, p.Arg294Gln variant affects one of the functional domains (aa 227-459; Peptidase S1 domain) in the F9 protein meeting PM1. The variant is absent from male population databases (gnomAD v4.1) meeting PM2_Supporting. At least 30 patients with mild, moderate or severe hemophilia B have been reported in the literature reviewed meeting PS4_Very Strong and PP4_Moderate (PMID:29296726, 15921378, 8091381). In-vitro functional studies show that the variant causes ER retention of the F9 protein, leading to reduced antigen levels meeting PS3_Supporting. REVEL score for this variant does not fall within the thresholds for pathogenic or benign predictions, and no splicing impact is noted by SpliceAI. 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 F9: PS4_Very Strong, PM1, PP4_Moderate, PS3_Supporting, PM2_Supporting. LINK:https://erepo.genome.network/evrepo/ui/classification/CA255368/MONDO:0010604/080

• Frequency:
  • Genomes: not found (cov: 23)
  • Exomes 𝑓: 0.0000018 (0 hom. 0 hem.)
• Consequence: F9 NM_000133.4 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:10
• Conservation: PhyloP100: 2.44

Genes affected

F9 (HGNC:3551): (coagulation factor IX) This gene encodes vitamin K-dependent coagulation factor IX that circulates in the blood as an inactive zymogen. This factor is converted to an active form by factor XIa, which excises the activation peptide and thus generates a heavy chain and a light chain held together by one or more disulfide bonds. The role of this activated factor IX in the blood coagulation cascade is to activate factor X to its active form through interactions with Ca+2 ions, membrane phospholipids, and factor VIII. Alterations of this gene, including point mutations, insertions and deletions, cause factor IX deficiency, which is a recessive X-linked disorder, also called hemophilia B or Christmas disease. Alternative splicing results in multiple transcript variants encoding different isoforms that may undergo similar proteolytic processing. [provided by RefSeq, Sep 2015]

ACMG classification

Verdict is Pathogenic. Variant got 11 ACMG points.

• PS3: For more information check the summary or visit ClinGen Evidence Repository.
• PS4: For more information check the summary or visit ClinGen Evidence Repository.
• PM1: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PP1: For more information check the summary or visit ClinGen Evidence Repository.
• PP4: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
F9	NM_000133.4	c.881G>A	p.Arg294Gln	missense_variant	8/8	ENST00000218099.7	NP_000124.1
F9	NM_001313913.2	c.767G>A	p.Arg256Gln	missense_variant	7/7		NP_001300842.1
F9	XM_005262397.5	c.752G>A	p.Arg251Gln	missense_variant	7/7		XP_005262454.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
F9	ENST00000218099.7	c.881G>A	p.Arg294Gln	missense_variant	8/8	1	NM_000133.4	ENSP00000218099	P1
F9	ENST00000394090.2	c.767G>A	p.Arg256Gln	missense_variant	7/7	1		ENSP00000377650
F9	ENST00000643157.1	n.1548G>A		non_coding_transcript_exon_variant	6/7

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome AF: 0.00000183 AC: 2 AN: 1094036 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 359734

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: 0.00000238

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 23

Bravo AF: 0.000219

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:10

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary factor IX deficiency disease Pathogenic:7

Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Aug 01, 2021	- -
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	Neuberg Centre For Genomic Medicine, NCGM	-	The missense variant p.R294Q in F9 (NM_000133.4 has been reported previously in affected patients with hemophilia B (Chavali et al, 2009; Yu et al, 2012). The p.R294Q variant is novel (not in any individuals) in gnomAD Exomes and is novel (not in any individuals) in 1000 Genomes. Experimental studies have shown that this missense change impairs intracellular trafficking of factor IX (Pignani et al, 2018). It has been submitted to ClinVar as Pathogenic. For these reasons, this variant has been classified as Pathogenic -
Pathogenic, no assertion criteria provided	literature only	OMIM	Mar 01, 1992	- -
Pathogenic, criteria provided, single submitter	clinical testing	3billion	-	The variant is not observed in the gnomAD v2.1.1 dataset. The variant is located in a mutational hot spot and/or well-established functional domain in which established pathogenic variants have been reported. Missense changes are a common disease-causing mechanism. In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.58; 3Cnet: 0.73). Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000010602 / PMID: 2472424). A different missense change at the same codon (p.Arg294Gly) has been reported to be associated with F9 related disorder (PMID: 7937052). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Mar 15, 2023	Variant summary: F9 c.881G>A (p.Arg294Gln) results in a conservative amino acid change located in the Serine proteases, trypsin domain (IPR001254) of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 179083 control chromosomes (gnomAD). c.881G>A has been reported in the literature in multiple individuals affected with Factor IX Deficiency (Hemophilia B) (Chen_1989, Chavali_2009, Onay_2003), including de novo occurrences. These data indicate that the variant is very likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Four ClinVar submitters (evaluation after 2014) cite this variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Pathogenic, criteria provided, single submitter	research	Division of Human Genetics, National Health Laboratory Service/University of the Witwatersrand	Jul 01, 2023	- -

Hereditary factor IX deficiency disease;C2749016:Thrombophilia, X-linked, due to factor 9 defect Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 17, 2023

This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 294 of the F9 protein (p.Arg294Gln). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with hemophilia B (PMID: 2472424, 19699296, 22544209, 32155688; Invitae). This variant is also known as p.Arg248Gln. ClinVar contains an entry for this variant (Variation ID: 10602). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on F9 protein function. Experimental studies have shown that this missense change affects F9 function (PMID: 29993188). For these reasons, this variant has been classified as Pathogenic. -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Mar 27, 2024

Published functional studies demonstrate a damaging effect (PMID: 29993188); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 31064749, 22639855, 1346975, 32155688, 32224444, 22544209, 19699296, 2472424, 12588353, 29993188) -

Hereditary factor VIII deficiency disease Pathogenic:1

Pathogenic, criteria provided, single submitter

research

NIHR Bioresource Rare Diseases, University of Cambridge

Feb 01, 2019

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.19
BayesDel_addAF	Pathogenic	0.31	D
BayesDel_noAF	Pathogenic	0.21
CADD	Uncertain	25
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.70	D;.
FATHMM_MKL	Benign	0.13	N
LIST_S2	Benign	0.79	T;T
M_CAP	Uncertain	0.27	D
MetaRNN	Pathogenic	0.97	D;D
MetaSVM	Uncertain	0.32	D
MutationAssessor	Benign	1.7	L;.
MutationTaster	Benign	5.9e-9	A;A
PrimateAI	Benign	0.26	T
PROVEAN	Benign	-1.5	N;N
REVEL	Uncertain	0.58
Sift	Benign	0.080	T;T
Sift4G	Benign	0.18	T;T
Polyphen		0.99	D;.
Vest4		0.33
MutPred		0.90		Loss of methylation at K293 (P = 0.0676);.;
MVP		0.99
MPC		1.8
ClinPred		0.93	D
GERP RS		5.4
Varity_R		0.87
gMVP		0.96

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs137852249; hg19: chrX-138643725; COSMIC: COSV54379618;