Genetic Variant HBB:p.Asn109GlnfsTer32 (chr11-5225718-G-GC) – ACMG Classification: Pathogenic (18 pts)

Variant summary

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

The NM_000518.5(HBB):c.323dupG(p.Asn109GlnfsTer32) variant causes a frameshift change. The variant allele was found at a frequency of 0.0000031 in 1,613,946 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. G108G) has been classified as Benign.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

HBB
NM_000518.5 frameshift

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:7

Conservation

PhyloP100: 4.33

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

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 49 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 11-5225718-G-GC is Pathogenic according to our data. Variant chr11-5225718-G-GC is described in ClinVar as [Pathogenic]. Clinvar id is 439153.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HBB	NM_000518.5 link	c.323dupG	p.Asn109GlnfsTer32	frameshift_variant	Exon 3 of 3	ENST00000335295.4	NP_000509.1	P68871D9YZU5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HBB	ENST00000335295.4 link	c.323dupG	p.Asn109GlnfsTer32	frameshift_variant	Exon 3 of 3	1	NM_000518.5	ENSP00000333994.3		P68871

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152186

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

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

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251204

Hom.:

AF XY:

0.00000737

AC XY:

AN XY:

135776

show subpopulations

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 SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000881

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000205

AC:

AN:

1461760

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727202

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:

0.0000166

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152186

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74346

show subpopulations

Gnomad4 AFR

AF:

0.0000483

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:

0.0000567

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:3

Feb 22, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. This variant disrupts a region of the HBB protein in which other variant(s) (p.Val127Glufs*8) have been determined to be pathogenic (PMID: 8535446, 31190580). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. ClinVar contains an entry for this variant (Variation ID: 439153). This premature translational stop signal has been observed in individual(s) with HBB-related conditions (PMID: 3683554). This variant is present in population databases (rs606231216, gnomAD 0.004%). This sequence change creates a premature translational stop signal (p.Asn109Glnfs*32) in the HBB gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 39 amino acid(s) of the HBB protein. -

Oct 12, 2022

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The HBB c.323dup (p.Asn109Glnfs*32) frameshift variant alters the translational reading frame of the HBB mRNA and causes the premature termination of HBB protein synthesis. In the published literature, the variant has been reported in individuals with beta-thalassemia (PMID: 3683554 (1987), 23590658 (2013)). Based on the available information, this variant is classified as pathogenic. -

Nov 08, 2024

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The HBB c.323dupG; p.Asn109GlnfsTer32 variant (rs35225141, HbVar ID: 945), also known as c.321_322insG and Codon 106/107 (+G), has been reported in individuals with beta(0) thalassemia (Hoppe 2013), and found with another pathogenic HBB variant (Wong 1987). This variant is reported as pathogenic in ClinVar (Variation ID: 439153). It is only observed on two alleles in the Genome Aggregation Database, indicating it is not a common polymorphism. This variant causes a frameshift by duplicating a single nucleotide, so it is predicted to result in a truncated protein or mRNA subject to nonsense-mediated decay. Based on available information, this variant is considered to be pathogenic. References: Link to HbVar database: https://globin.bx.psu.edu/hbvar/menu.html Hoppe CC. Prenatal and newborn screening for hemoglobinopathies. Int J Lab Hematol. 2013 Jun;35(3):297-305. PMID: 23590658. Wong C et al. Characterization of beta-thalassaemia mutations using direct genomic sequencing of amplified single copy DNA. Nature. 1987 Nov 26-Dec 2;330(6146):384-6. PMID: 3683554. -

beta Thalassemia

Pathogenic:2

Jul 03, 2017

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

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: The c.323dupG (p.Asn109Glnfs) variant in HBB gene is a frameshift change that is predicted to cause loss of normal protein function through protein truncation or nonsense-mediated mRNA decay. The variant is absent from the large control population dataset of ExAC, but is present at a low frequency in gnomAD dataset (0.000007; 2/276928 chrs tested), which does not exceed exceed the estimated maximal expected allele frequency of a pathogenic variant (0.011). The variant has been reported in several affected individuals presented with b-thalassemia major via published reports and is cited by reputable databases/clinical laboratories as Pathogenic. Taking together, the variant was classified as Pathogenic. -

Nov 25, 2019

The ITHANET community portal, The Cyprus Institute of Neurology and Genetics

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: curation

- -

Beta zero thalassemia

Pathogenic:1

Nov 26, 1987

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Hb SS disease;C0019025:Hereditary persistence of fetal hemoglobin;C0700299:Heinz body anemia;C1840779:METHEMOGLOBINEMIA, BETA TYPE;C1858990:Dominant beta-thalassemia;C1970028:Malaria, susceptibility to;C4693822:Erythrocytosis, familial, 6;CN322236:Beta-thalassemia HBB/LCRB

Pathogenic:1

Jan 24, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

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

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