Variant rs33945777 details in Genebe, Genetics Data Aggregator

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_000518.5(HBB):c.315+1G>T variant causes a splice donor, intron change. The variant allele was found at a frequency of 0.00000657 in 152,150 control chromosomes in the GnomAD database, with no homozygous occurrence. 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)

Consequence

HBB
NM_000518.5 splice_donor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:4

Conservation

PhyloP100: 5.66

Variant links:

Genes affected

HBB (HGNC:4827): (hemoglobin subunit beta) The alpha (HBA) and beta (HBB) loci determine the structure of the 2 types of polypeptide chains in adult hemoglobin, Hb A. The normal adult hemoglobin tetramer consists of two alpha chains and two beta chains. Mutant beta globin causes sickle cell anemia. Absence of beta chain causes beta-zero-thalassemia. Reduced amounts of detectable beta globin causes beta-plus-thalassemia. The order of the genes in the beta-globin cluster is 5'-epsilon -- gamma-G -- gamma-A -- delta -- beta--3'. [provided by RefSeq, Jul 2008]

HBB links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 18 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 3.4, offset of -47, new splice context is: tgaGTgagc. 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 11-5226576-C-A is Pathogenic according to our data. Variant chr11-5226576-C-A is described in ClinVar as [Pathogenic]. Clinvar id is 619686.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr11-5226576-C-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HBB	NM_000518.5 link	c.315+1G>T		splice_donor_variant, intron_variant	Intron 2 of 2	ENST00000335295.4	NP_000509.1	P68871D9YZU5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HBB	ENST00000335295.4 link	c.315+1G>T		splice_donor_variant, intron_variant	Intron 2 of 2	1	NM_000518.5	ENSP00000333994.3		P68871

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152150

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

Cov.:

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152150

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74304

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

beta Thalassemia

Pathogenic:2

May 03, 2020

Genomic Research Center, Shahid Beheshti University of Medical Sciences

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Feb 12, 2019

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: HBB c.315+1G>T is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Several computational tools predict a significant impact on normal splicing: Four predict the variant abolishes a 5' splicing donor site. However, these predictions have yet to be confirmed by functional studies. The variant was absent in 276896 control chromosomes. c.315+1G>T has been reported in the literature in individuals affected with Beta Thalassemia. These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as pathogenic. -

not provided

Pathogenic:2

Aug 09, 2024

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The HBB c.315+1G>T variant (also known as IVS-II-1 (G>T)) disrupts a canonical splice-donor site and interferes with normal HBB mRNA splicing. The frequency of this variant in the general population, 0.0000066 (1/152150 chromosomes, http://gnomad.broadinstitute.org), is consistent with pathogenicity. In the published literature, the variant has been reported in individuals with beta-thalassemia (PMID: 3828533 (1987), PMID: 20524821 (2010)). Based on the available information, this variant is classified as pathogenic. Genetic counseling and testing of at-risk relatives are recommended. -

Jul 10, 2021

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The HBB c.315+1G>T variant (rs33945777), also known as IVS II-1 (G>T), is reported in the literature in individuals affected with beta(0) thalassemia (see HbVar, Broquere 2010, Chehab 1987). This variant is reported in ClinVar (Variation ID: 619686). This variant is absent from the Genome Aggregation Database, indicating it is not a common polymorphism. This variant disrupts the canonical splice donor site of intron 2, which is likely to negatively impact gene function. Based on available information, this variant is considered to be pathogenic. References: Link to HbVar database for c.315+1G>T: http://globin.bx.psu.edu/cgi-bin/hbvar/query_vars3?mode=output&display_format=page&i=2602&.cgifields=histD Broquere C et al. Phenotypic expression and origin of the rare beta-thalassemia splice site mutation HBB:c.315 + 1G>T. Hemoglobin. 2010 Jun;34(3):322-6. Chehab FF et al. The molecular basis of beta-thalassemia in Lebanon: application to prenatal diagnosis. Blood. 1987 Apr;69(4):1141-5. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.60

BayesDel_noAF

Pathogenic

0.28

CADD

Pathogenic

DANN

Uncertain

0.99

Eigen

Pathogenic

1.0

Eigen_PC

Pathogenic

0.82

FATHMM_MKL

Pathogenic

0.97

GERP RS

4.7

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_DG_spliceai

0.99

Position offset: 2

DS_DL_spliceai

1.0

Position offset: 1

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over