11-5225728-T-G

Variant summary

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

The NM_000518.5(HBB):​c.316-2A>C variant causes a splice acceptor, intron change. The variant allele was found at a frequency of 0.00000124 in 1,613,796 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: 33)
Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

HBB
NM_000518.5 splice_acceptor, intron

Scores

5
1
1
Splicing: ADA: 1.000
2

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:6O:1

Conservation

PhyloP100: 5.51
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]

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,
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 11-5225728-T-G is Pathogenic according to our data. Variant chr11-5225728-T-G is described in ClinVar as [Pathogenic]. Clinvar id is 21190.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr11-5225728-T-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
HBBNM_000518.5 linkc.316-2A>C splice_acceptor_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
HBBENST00000335295.4 linkc.316-2A>C splice_acceptor_variant, intron_variant Intron 2 of 2 1 NM_000518.5 ENSP00000333994.3 P68871
HBBENST00000647020.1 linkc.316-2A>C splice_acceptor_variant, intron_variant Intron 2 of 2 ENSP00000494175.1 P68871
HBBENST00000475226.1 linkn.248-2A>C splice_acceptor_variant, intron_variant Intron 1 of 1 2
HBBENST00000633227.1 linkn.*132-2A>C splice_acceptor_variant, intron_variant Intron 2 of 2 3 ENSP00000488004.1 A0A0J9YWK4

Frequencies

GnomAD3 genomes
AF:
0.00000658
AC:
1
AN:
152090
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.0000242
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
AF:
6.84e-7
AC:
1
AN:
1461706
Hom.:
0
Cov.:
31
AF XY:
0.00
AC XY:
0
AN XY:
727164
show subpopulations
Gnomad4 AFR exome
AF:
0.0000299
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:
0.00
Gnomad4 OTH exome
AF:
0.00
GnomAD4 genome
AF:
0.00000658
AC:
1
AN:
152090
Hom.:
0
Cov.:
33
AF XY:
0.0000135
AC XY:
1
AN XY:
74276
show subpopulations
Gnomad4 AFR
AF:
0.0000242
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

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:6Other:1
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

beta Thalassemia Pathogenic:2Other:1
Pathogenic, no assertion criteria providedcurationThe ITHANET community portal, The Cyprus Institute of Neurology and GeneticsNov 25, 2019- -
not provided, no classification providedliterature onlyGeneReviews-- -
Pathogenic, no assertion criteria providedclinical testingNatera, Inc.Mar 17, 2017- -
not provided Pathogenic:2
Pathogenic, criteria provided, single submitterclinical testingLabcorp Genetics (formerly Invitae), LabcorpJun 14, 2022Disruption of this splice site has been observed in individuals with beta thalassemia (PMID: 2123063, 6583702). It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (gnomAD no frequency). This sequence change affects an acceptor splice site in intron 2 of the HBB gene. While this variant is not anticipated to result in nonsense mediated decay, it likely alters RNA splicing and results in a disrupted protein product. ClinVar contains an entry for this variant (Variation ID: 21190). For these reasons, this variant has been classified as Pathogenic. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that disruption of this splice site is associated with altered splicing resulting in unknown protein product impact (PMID: 6583702). -
Pathogenic, criteria provided, single submitterclinical testingQuest Diagnostics Nichols Institute San Juan CapistranoNov 08, 2021This variant (also known as IVS-II-849 (A>C)) is located in the canonical splice-acceptor site of intron 2 of the HBB gene, and disrupts normal splicing of the beta-globin mRNA. The variant is associated with beta(0)-thalassemia (PMID: 2424301 (1986)). It has not been reported in large, multi-ethnic general populations (http://gnomad.broadinstitute.org). Based on the available information, this variant is classified as pathogenic. -
Beta zero thalassemia Pathogenic:1
Pathogenic, no assertion criteria providedliterature onlyOMIMJul 01, 1986- -
Beta-thalassemia major Pathogenic:1
Pathogenic, criteria provided, single submitterclinical testingWomen's Health and Genetics/Laboratory Corporation of America, LabCorpMar 10, 2022Variant summary: HBB c.316-2A>C (also known as IVS II-849A>C in the literature) 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 canonical 3 prime acceptor site. However, these predictions have yet to be confirmed by functional studies. Blot hybridization analysis of RNA prepared from the erythoid cells of the patient who carried the variant and was diagnosed with HbS-beta0 thalassemia showed only RNA of normal size. The authors postulated that this may be attributed to the rapid degradation of the abnormal RNA or to the complete absence of an abnormally processed RNA (Padanilam et al, 1986). The variant was absent in 251048 control chromosomes (gnomAD). c.316-2A>C has been reported in the literature in at least an individual affected with Beta Thalassemia Major (Chouk_2004, Padanilam_1986). These data indicate that the variant is very likely to be associated with disease.Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 and all classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.60
D
BayesDel_noAF
Pathogenic
0.29
CADD
Pathogenic
27
DANN
Uncertain
0.99
Eigen
Pathogenic
1.0
Eigen_PC
Pathogenic
0.82
FATHMM_MKL
Pathogenic
0.97
D
GERP RS
4.7

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
1.0
dbscSNV1_RF
Pathogenic
0.93
SpliceAI score (max)
0.98
Details are displayed if max score is > 0.2
DS_AL_spliceai
0.98
Position offset: -2

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.

Other links and lift over

dbSNP: rs33914668; hg19: chr11-5246958; API