chr11-5227017-A-G

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 6P and 1B. PM1PM2PP3_ModerateBP6

The NM_000518.5(HBB):c.5T>C(p.Val2Ala) variant causes a missense change. The variant allele was found at a frequency of 0.0000025 in 1,596,872 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V2M) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

HBB
NM_000518.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:1O:1

Conservation

PhyloP100: 4.96

Publications

15 publications found

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 Gene-Disease associations (from GenCC):

dominant beta-thalassemia
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), ClinGen
hemoglobin M disease
Inheritance: AD Classification: DEFINITIVE, MODERATE, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics, ClinGen
beta thalassemia
Inheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health
beta-thalassemia HBB/LCRB
Inheritance: AR, SD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics
sickle cell disease and related diseases
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
erythrocytosis, familial, 6
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp
Heinz body anemia
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
sickle cell disease
Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae)
hereditary persistence of fetal hemoglobin-beta-thalassemia syndrome
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
beta-thalassemia intermedia
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
beta-thalassemia major
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
delta-beta-thalassemia
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
hemoglobin C disease
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
hemoglobin C-beta-thalassemia syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
hemoglobin E disease
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
hemoglobin E-beta-thalassemia syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
hereditary persistence of fetal hemoglobin-sickle cell disease syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
sickle cell-beta-thalassemia disease syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
sickle cell-hemoglobin c disease syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
sickle cell-hemoglobin d disease syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
sickle cell-hemoglobin E disease syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

HBB links:

ENSG00000298932 (HGNC:):

ENSG00000298932 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

PM1

In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 7 benign, 18 uncertain in NM_000518.5

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.886

BP6

Variant 11-5227017-A-G is Benign according to our data. Variant chr11-5227017-A-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 15323.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HBB	NM_000518.5 link	c.5T>C	p.Val2Ala	missense_variant	Exon 1 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.5T>C	p.Val2Ala	missense_variant	Exon 1 of 3	1	NM_000518.5	ENSP00000333994.3		P68871

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152192

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:

0.00

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:

0.00000398

AC:

AN:

251128

AF XY:

0.00

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 FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000881

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000208

AC:

AN:

1444680

Hom.:

Cov.:

AF XY:

0.00000278

AC XY:

AN XY:

719938

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33096

American (AMR)

AF:

0.00

AC:

AN:

44716

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26032

East Asian (EAS)

AF:

0.00

AC:

AN:

39652

South Asian (SAS)

AF:

0.00

AC:

AN:

86014

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53404

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5726

European-Non Finnish (NFE)

AF:

0.00000182

AC:

AN:

1096270

Other (OTH)

AF:

0.0000167

AC:

AN:

59770

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00462622), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.358

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152192

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74364

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41444

American (AMR)

AF:

0.00

AC:

AN:

15286

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5196

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68032

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.625

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000282

Hom.:

Bravo

AF:

0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:1Other:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Nov 29, 2017

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

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: The HBB c.5T>C (p.Val2Ala) variant, also known as Hb Raleigh, causes a missense change involving the alteration of a conserved nucleotide and 4/4 in silico tools predict a damaging outcome for this variant (SNPsandGO not captured due to low reliability index). Functional studies showed that Hb Raleigh had a lower oxygen affinity than Hb A throughout the pH range examined but did not affect protein stability (Moo-Penn_1977, Landin_1993). Also, 2,3-diphosphoglycerate and inositol hexaphosphate cofactors addition had less effect on the oxygen affinity of Hb Raleigh than on that of Hb A with chloride ions having the opposite effect. This variant was found in 1/245880 control chromosomes (gnomAD) at a frequency of 0.0000041, which does not exceed the estimated maximal expected allele frequency of a pathogenic HBB variant (0.0111803). This variant is widely regarded as clinically silent variant. It was reported in several individuals with no clinical data (Chen_1998, Thongnoppakhun_2009, Canatan_2016,) or normal hematological values in heterozygosity (Landin_2009), including one report where it was occurring in 5 members of the same family where the proband (compound heterozygous with Hb Russ) had normal hematological values (Moo Penn_1977). In addition, an individual who had this variant in compound heterozygous state with HbS showed no specific features of hemoglobinopathy or beta-thalassemia (Sofronescu_2011). Furthermore, an individual, who was a double heterozygote for this variant and alfa gene deletion (c.a-3.7), was generally healthy but had a mild anemia due to the alfa gene deletion (Jain_2011). This structural variant produces spurious HbA1c measurement depending upon methods used, impeding the use of Hb glycosylation as a means to monitor glucose control in diabetic patients with Hb-Raleigh (Chen_1998, Vandewiele_2010, Sofronescu_2011, Singha_2011, Jain_2011). Taken together, this variant is classified as a VUS-possibly benign. -

beta Thalassemia

Uncertain:1

Oct 24, 2018

Natera, Inc.

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

not provided

Benign:1

May 27, 2024

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The Hb Raleigh variant (HBB: c.5T>C; p.Val2Ala, also known as Val1Ala when numbered from the mature protein; HbVar ID: 217; rs33949930) has been described in the heterozygous state in asymptomatic individuals with normal hematological parameters (HbVar and references therein). This variant is reported in ClinVar (Variation ID: 15323), and is found on only one chromosome (1/251128 alleles) in the Genome Aggregation Database. The valine at codon 2 is highly conserved and functional studies of this variant protein demonstrate reduced oxygen affinity and dissociation (HbVar and references therein). Additionally, this variant has been reported to interfere with measurements of HbA1c (Sofronescu 2011). Based on available information, this variant is considered to be likely benign. References: Link to HbVar: https://globin.bx.psu.edu/hbvar/menu.html Sofronescu AG et al. Unexpected hemoglobin A1c results. Clin Chem. 2011 Feb;57(2):153-6. PMID: 21278358. -

HEMOGLOBIN RALEIGH

Other:1

Dec 12, 2017

OMIM

Significance:other

Review Status:no assertion criteria provided

Collection Method:literature only

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.67

BayesDel_addAF

Pathogenic

0.41

BayesDel_noAF

Pathogenic

0.35

CADD

Benign

(source)

DANN

Benign

0.96

DEOGEN2

Benign

0.11

T;T;.;T

Eigen

Benign

0.16

Eigen_PC

Benign

0.10

FATHMM_MKL

Uncertain

0.96

LIST_S2

Benign

0.78

.;T;T;T

M_CAP

Pathogenic

0.43

MetaRNN

Pathogenic

0.89

D;D;D;D

MetaSVM

Uncertain

0.54

MutationAssessor

Pathogenic

3.4

M;M;.;.

PhyloP100

5.0

PrimateAI

Uncertain

0.73

PROVEAN

Uncertain

-2.5

D;.;.;D

REVEL

Pathogenic

0.79

Sift

Uncertain

0.0030

D;.;.;D

Sift4G

Uncertain

0.0040

D;.;.;.

Polyphen

0.88

P;P;.;.

Vest4

0.87

MutPred

0.70

Loss of stability (P = 0.0128);Loss of stability (P = 0.0128);Loss of stability (P = 0.0128);Loss of stability (P = 0.0128);

MVP

0.80

MPC

0.043

ClinPred

0.78

GERP RS

4.0

PromoterAI

0.16

Neutral

(source)

Varity_R

0.34

gMVP

0.83

Mutation Taster

=16/84

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over