rs750609759

Variant names:

• chr7-100627822-T-C
• rs750609759
• NM_003227.4:c.1606-2A>G

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_003227.4(TFR2):​c.1606-2A>G variant causes a splice acceptor, intron change. The variant allele was found at a frequency of 0.0000725 in 1,613,868 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000079 (1 hom.)
• Consequence: TFR2 NM_003227.4 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 5.95
• Publications: 0 publications found

Genes affected

TFR2 (HGNC:11762): (transferrin receptor 2) This gene encodes a single-pass type II membrane protein, which is a member of the transferrin receptor-like family. This protein mediates cellular uptake of transferrin-bound iron, and may be involved in iron metabolism, hepatocyte function and erythrocyte differentiation. Mutations in this gene have been associated with hereditary hemochromatosis type III. Alternatively spliced transcript variants encoding different isoforms have been described for this gene. [provided by RefSeq, May 2011]

TFR2 Gene-Disease associations (from GenCC):

• hemochromatosis type 3

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), Orphanet, Genomics England PanelApp, G2P

ENSG00000298392 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 4.2, offset of 20, new splice context is: gtggattctcccaaccacAGtgg. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 7-100627822-T-C is Pathogenic according to our data. Variant chr7-100627822-T-C is described in ClinVar as Pathogenic. ClinVar VariationId is 570407.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_003227.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TFR2	NM_003227.4	MANE Select	c.1606-2A>G		splice_acceptor intron	N/A	NP_003218.2
	TFR2	NM_001206855.3		c.1093-2A>G		splice_acceptor intron	N/A	NP_001193784.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TFR2	ENST00000223051.8	TSL:1 MANE Select	c.1606-2A>G		splice_acceptor intron	N/A	ENSP00000223051.3
	TFR2	ENST00000462107.1	TSL:5	c.1606-2A>G		splice_acceptor intron	N/A	ENSP00000420525.1
	TFR2	ENST00000431692.5	TSL:5	c.*281-2A>G		splice_acceptor intron	N/A	ENSP00000413905.1

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 151994 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000159 AC: 4 AN: 251464 AF XY: 0.0000221

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000264

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.0000794 AC: 116 AN: 1461874 Hom.: 1 Cov.: 41 AF XY: 0.0000743 AC XY: 54 AN XY: 727248

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.000103 AC: 115 AN: 1112000

Other (OTH) AF: 0.0000166 AC: 1 AN: 60396

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 151994 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74234

African (AFR) AF: 0.00 AC: 0 AN: 41378

American (AMR) AF: 0.00 AC: 0 AN: 15258

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5184

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10588

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 67970

Other (OTH) AF: 0.00 AC: 0 AN: 2086

Alfa AF: 0.0000419 Hom.: 0

Bravo AF: 0.0000264

TwinsUK AF: 0.000270 AC: 1

ALSPAC AF: 0.00 AC: 0

ExAC AF: 0.0000165 AC: 2

EpiCase AF: 0.0000545

EpiControl AF: 0.0000593

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hemochromatosis type 3 Pathogenic:1

Feb 25, 2024

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Hereditary hemochromatosis Pathogenic:1

Mar 18, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects an acceptor splice site in intron 13 of the TFR2 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in TFR2 are known to be pathogenic (PMID: 23600741, 26029709). This variant is present in population databases (rs750609759, gnomAD 0.004%). Disruption of this splice site has been observed in individual(s) with type 3 hereditary haemochromatosis (PMID: 28276324). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 570407). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Benign	-0.10
CADD	Pathogenic	34
DANN	Uncertain	0.99
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Uncertain	0.93	D
PhyloP100		6.0
GERP RS		5.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Mutation Taster		=3/97	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.95
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.73		Position offset: -22
DS_AL_spliceai		1.0		Position offset: -2

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

Other links and lift over

dbSNP: rs750609759; hg19: chr7-100225445;