NM_000133.4:c.223C>T

Variant names:

• chrX-139537144-C-T
• rs137852227
• NM_000133.4:c.223C>T

Variant summary

Our verdict is Pathogenic. The variant received 15 ACMG points: 15P and 0B. PS4 PVS1 PP4_Moderate PM2_Supporting

This summary comes from the ClinGen Evidence Repository: The F9 c.223C>T; p.Arg75Ter causes a protein truncation that is expected to undergo NMD, meeting PVS1. The variant is completely absent from gnomAD v2.1.1 and v3.1.1, meeting PM2_Supporting. Over 75 patients are reported in the literature with moderate-severe hemophilia B, some with a history of inhibitors to factor replacement products, meeting F9 phenotype criteria for PS4_Very strong and PP4_Moderate (EAHAD database; PMID:29296726). 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: PVS1, PS4_Very strong, PP4_Moderate, PM2_Supporting. LINK:https://erepo.genome.network/evrepo/ui/classification/CA340993/MONDO:0010604/080

• Frequency: Genomes: not found (cov: 23)
• Consequence: F9 NM_000133.4 stop_gained
• Clinical Significance: Pathogenic reviewed by expert panel P:6 O:1
• Conservation: PhyloP100: 0.808
• Publications: 14 publications found

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]

F9 Gene-Disease associations (from GenCC):

• hemophilia B

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

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

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

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

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet
• thrombophilia, X-linked, due to factor 9 defect

  Inheritance: XL Classification: LIMITED Submitted by: ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 15 ACMG points.

• PVS1: For more information check the summary or visit ClinGen Evidence Repository.
• PS4: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PP4: For more information check the summary or visit ClinGen Evidence Repository.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000133.4. 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
	F9	NM_000133.4	MANE Select	c.223C>T	p.Arg75*	stop_gained	Exon 2 of 8	NP_000124.1	P00740-1
	F9	NM_001313913.2		c.223C>T	p.Arg75*	stop_gained	Exon 2 of 7	NP_001300842.1	P00740-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	F9	ENST00000218099.7	TSL:1 MANE Select	c.223C>T	p.Arg75*	stop_gained	Exon 2 of 8	ENSP00000218099.2	P00740-1
	F9	ENST00000394090.2	TSL:1	c.223C>T	p.Arg75*	stop_gained	Exon 2 of 7	ENSP00000377650.2	P00740-2
	F9	ENST00000479617.2	TSL:5	n.230C>T		non_coding_transcript_exon	Exon 2 of 4

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 23

Alfa AF: 0.00 Hom.: 0

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: reviewed by expert panel

Pathogenic	VUS	Benign	Condition
3	-	-	Hereditary factor IX deficiency disease (4)
2	-	-	not provided (2)
1	-	-	Hereditary factor IX deficiency disease;C2749016:Thrombophilia, X-linked, due to factor 9 defect (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.74	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	35
DANN	Uncertain	1.0
FATHMM_MKL	Benign	0.67	D
PhyloP100		0.81
Vest4		0.94
GERP RS		5.2
Mutation Taster		=1/199	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs137852227; hg19: chrX-138619303; COSMIC: COSV54378708;