NM_000517.6:c.150C>A

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1PP3_Moderate

The NM_000517.6(HBA2):c.150C>A(p.Ser50Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Likely benign in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S50N) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 13)

Exomes 𝑓: 0.0000012 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

HBA2
NM_000517.6 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1O:1

Conservation

PhyloP100: 0.341

Publications

2 publications found

Variant links:

Genes affected

HBA2 (HGNC:4824): (hemoglobin subunit alpha 2) The human alpha globin gene cluster located on chromosome 16 spans about 30 kb and includes seven loci: 5'- zeta - pseudozeta - mu - pseudoalpha-1 - alpha-2 - alpha-1 - theta - 3'. The alpha-2 (HBA2) and alpha-1 (HBA1) coding sequences are identical. These genes differ slightly over the 5' untranslated regions and the introns, but they differ significantly over the 3' untranslated regions. Two alpha chains plus two beta chains constitute HbA, which in normal adult life comprises about 97% of the total hemoglobin; alpha chains combine with delta chains to constitute HbA-2, which with HbF (fetal hemoglobin) makes up the remaining 3% of adult hemoglobin. Alpha thalassemias result from deletions of each of the alpha genes as well as deletions of both HBA2 and HBA1; some nondeletion alpha thalassemias have also been reported. [provided by RefSeq, Jul 2008]

HBA2 Gene-Disease associations (from GenCC):

alpha thalassemia spectrum
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen
erythrocytosis, familial, 7
Inheritance: AD Classification: STRONG, LIMITED Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
hemoglobin M disease
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Hb Bart's hydrops fetalis
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
hemoglobin H disease
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
Heinz body anemia
Inheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)
methemoglobinemia, alpha type
Inheritance: AD Classification: LIMITED Submitted by: ClinGen

HBA2 links:

ENSG00000294455 (HGNC:):

ENSG00000294455 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 4 benign, 10 uncertain in NM_000517.6

PP3

MetaRNN computational evidence supports a deleterious effect, 0.875

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HBA2	NM_000517.6 link	c.150C>A	p.Ser50Arg	missense_variant	Exon 2 of 3	ENST00000251595.11	NP_000508.1	P69905D1MGQ2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HBA2	ENST00000251595.11 link	c.150C>A	p.Ser50Arg	missense_variant	Exon 2 of 3	1	NM_000517.6	ENSP00000251595.6		P69905

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00

AC:

AN:

126992

AF XY:

0.00

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

Data not reliable, filtered out with message: AS_VQSR

AF:

0.00000120

AC:

AN:

835174

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

431174

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:

17810

American (AMR)

AF:

0.00

AC:

AN:

35976

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

21352

East Asian (EAS)

AF:

0.00

AC:

AN:

33608

South Asian (SAS)

AF:

0.00

AC:

AN:

67340

European-Finnish (FIN)

AF:

0.00

AC:

AN:

34342

Middle Eastern (MID)

AF:

0.00

AC:

AN:

2898

European-Non Finnish (NFE)

AF:

0.00000172

AC:

AN:

582706

Other (OTH)

AF:

0.00

AC:

AN:

39142

⚠️ 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: 0.225

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

Cov.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1Other:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not provided

Uncertain:1

May 19, 2022

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

HEMOGLOBIN SAVARIA

Other:1

Jul 20, 2016

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

Uncertain

0.50

BayesDel_addAF

Pathogenic

0.40

BayesDel_noAF

Pathogenic

0.34

CADD

Benign

(source)

DANN

Uncertain

0.99

DEOGEN2

Benign

0.041

.;T

Eigen

Benign

-0.032

Eigen_PC

Benign

-0.21

FATHMM_MKL

Benign

0.32

M_CAP

Pathogenic

0.55

MetaRNN

Pathogenic

0.87

D;D

MetaSVM

Pathogenic

0.81

PhyloP100

0.34

PrimateAI

Uncertain

0.60

PROVEAN

Uncertain

-2.6

D;D

REVEL

Pathogenic

0.73

Sift

Pathogenic

0.0

D;D

Sift4G

Benign

0.10

T;T

Vest4

0.68

MutPred

0.64

Gain of solvent accessibility (P = 0.0155);.;

MVP

1.0

MPC

2.3

ClinPred

0.99

GERP RS

3.2

PromoterAI

-0.0055

Neutral

(source)

gMVP

0.87

Mutation Taster

=2/98

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.040

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