11-5225615-C-T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 4P and 1B. PM1PM2BP4

The NM_000518.5(HBB):c.427G>A(p.Ala143Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,820 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A143V) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

HBB
NM_000518.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 1.69

Publications

1 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 3 ACMG points.

PM1

In a hotspot region, there are 14 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 25 uncertain in NM_000518.5

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.42103812).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HBB	NM_000518.5 link	c.427G>A	p.Ala143Thr	missense_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.427G>A	p.Ala143Thr	missense_variant	Exon 3 of 3	1	NM_000518.5	ENSP00000333994.3		P68871

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1461820

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727216

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:

33478

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39698

South Asian (SAS)

AF:

0.0000232

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53412

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111954

Other (OTH)

AF:

0.00

AC:

AN:

60394

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.350

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Aug 06, 2024

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: HBB c.427G>A (p.Ala143Thr) results in a non-conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251382 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.427G>A has been reported in the literature in individuals without clinical or hematological abnormalities (Hoyer_2002). These reports do not provide unequivocal conclusions about association of the variant with Beta Thalassemia. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 12403495). ClinVar contains an entry for this variant (Variation ID: 801193). Based on the evidence outlined above, the variant was classified as uncertain significance. -

not provided

Uncertain:1

Nov 18, 2018

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.73

BayesDel_addAF

Pathogenic

0.21

BayesDel_noAF

Uncertain

0.070

CADD

Benign

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.027

T;T

Eigen

Benign

-0.13

Eigen_PC

Benign

-0.015

FATHMM_MKL

Uncertain

0.84

LIST_S2

Uncertain

0.86

.;D

M_CAP

Uncertain

0.25

MetaRNN

Benign

0.42

T;T

MetaSVM

Uncertain

0.25

MutationAssessor

Benign

2.0

M;M

PhyloP100

1.7

PrimateAI

Benign

0.48

PROVEAN

Benign

-2.2

N;.

REVEL

Uncertain

0.57

Sift

Benign

0.031

D;.

Sift4G

Benign

0.34

T;.

Polyphen

0.35

B;B

Vest4

0.63

MutPred

0.38

Gain of catalytic residue at A143 (P = 0.0249);Gain of catalytic residue at A143 (P = 0.0249);

MVP

0.69

MPC

0.037

ClinPred

0.67

GERP RS

3.8

Varity_R

0.24

gMVP

0.81

Mutation Taster

=7/93

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

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

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over