Variant rs281864524 details in Genebe, Genetics Data Aggregator

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2BP4_Strong

The ENST00000647020.1(HBB):c.-100G>A variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000024 in 833,510 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000022 ( 0 hom. )

Consequence

HBB
ENST00000647020.1 5_prime_UTR

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 0.0570

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 Likely_benign. Variant got -2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.54).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
HBB	NM_000518.5 linkuse as main transcript			upstream_gene_variant		ENST00000335295.4	NP_000509.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
HBB	ENST00000335295.4 linkuse as main transcript			upstream_gene_variant		1	NM_000518.5	ENSP00000333994	P1

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152182

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00116

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:

0.0000220

AC:

AN:

681210

Hom.:

Cov.:

AF XY:

0.0000247

AC XY:

AN XY:

363938

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.000372

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000479

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000328

AC:

AN:

152300

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74468

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000968

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000189

Asia WGS

AF:

0.000577

AC:

AN:

3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Aug 15, 2023

Variant summary: HBB c.-100G>A is located in the untranscribed region upstream of the HBB gene region. The variant allele was found at a frequency of 3.2e-05 in 31396 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance.c.-100G>A was initially reported in compound heterozygosity with pathogenic variant c.126_129delCTTT in a Chinese boy affected with Beta Thalassemia Major (Li_2009). However, a recent study reported the variant in eight simple heterozygotes with normal hematological parameters and it two compound heterozygous individuals (with known pathogenic variants c.126_129delCTTT and c.316-197C>T) with typical hematological parameters of b-thal trait. The authors of this study concluded that c.-100G>A is likely a silent beta-thal allele (Zhao_2020). Additionally, other recent studies reported detection of the variant in a large number of carrier Chinese individuals (e.g. He_2017, Zhang_2019, Peng_2021, Tan_2021). Of particular interest is the reporting of individuals with hematological parameters indicative of carrier status who were found to be homozygous for the variant of interest (n=1) or had other known pathogenic HBB variants (c.126_129delCTTT, c.217dupA) (e.g. He_2017, Zhang_2019). These data do not allow any conclusion about variant significance. Experimental evidence evaluating an impact on protein function demonstrated the variant results in mildly reduced mRNA levels and promoter activity (Li_2009, Kircher_2019). The following publications have been ascertained in the context of this evaluation (PMID: 28125089, 31395865, 19290524, 32986258, 25526804, 33439495, 25471338, 24055728, 30809867, 32674615, 36519257, 35119136). Three submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. All submitters classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

beta Thalassemia

Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Natera, Inc.

Sep 16, 2020

- -

alpha Thalassemia;C0002895: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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 20, 2021

- -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Quest Diagnostics Nichols Institute San Juan Capistrano

Aug 24, 2023

The HBB c.-100G>A variant has been reported in the published literature in an individual with beta-thalassemia major who was a compound heterozygote for this variant and the HBB c.126_129delCTTT (CDs 41–42 (-TTCT) variant (PMID: 19290524 (2009)). It has also been identified in carrier screens in the Chinese population (PMIDs: 33439495 (2021), 32986258 (2021), 30275481 (2019), 30809867 (2019), 28125089 (2017)). It has been described as a beta(+) variant. Functional studies suggest conflicting reports as to whether or not this variant impacts protein function (PMIDs: 31395865 (2019) and 19290524 (2009)). The frequency of this variant in the general population, 0.000032 (1/31396 chromosomes (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is uninformative in the assessment of its pathogenicity. Based on the available information, we are unable to determine the clinical significance of this variant. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.54

CADD

Benign

DANN

Benign

0.82

Splicing

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