chr16-173471-G-A

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate

The NM_000517.6(HBA2):c.301-1G>A variant causes a splice acceptor, intron change. The variant allele was found at a frequency of 0.000000686 in 1,457,858 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

Frequency

Genomes: not found (cov: 25)

Exomes 𝑓: 6.9e-7 ( 0 hom. )

Consequence

HBA2
NM_000517.6 splice_acceptor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Likely pathogenic criteria provided, single submitter P:3O:1

Conservation

PhyloP100: 6.58

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: Pathogenic. The variant received 12 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 16-173471-G-A is Pathogenic according to our data. Variant chr16-173471-G-A is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 15668.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HBA2	NM_000517.6 link	c.301-1G>A		splice_acceptor_variant, intron_variant	Intron 2 of 2	ENST00000251595.11	NP_000508.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HBA2	ENST00000251595.11 link	c.301-1G>A		splice_acceptor_variant, intron_variant	Intron 2 of 2	1	NM_000517.6	ENSP00000251595.6

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.86e-7

AC:

AN:

1457858

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

725062

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

31192

American (AMR)

AF:

0.00

AC:

AN:

44684

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26096

East Asian (EAS)

AF:

0.00

AC:

AN:

39684

South Asian (SAS)

AF:

0.00

AC:

AN:

85196

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53228

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5692

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111894

Other (OTH)

AF:

0.00

AC:

AN:

60192

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

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: Likely pathogenic

Submissions summary: Pathogenic:3Other:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

alpha Thalassemia

Pathogenic:1

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

Hemoglobin H disease, nondeletional

Pathogenic:1

Aug 01, 2001

OMIM

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

alpha Thalassemia;C0700299:Heinz body anemia;C3161174:Hemoglobin H disease;C4693823:Erythrocytosis, familial, 7

Pathogenic:1

Nov 12, 2021

Fulgent Genetics, Fulgent Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

HEMOGLOBIN CLINICO-MADRID

Other:1

Mar 28, 2013

OMIM

Significance:other

Review Status:no assertion criteria provided

Collection Method:literature only

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.60

BayesDel_noAF

Pathogenic

0.18

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

DEOGEN2

Benign

0.0

.;.

Eigen

Pathogenic

1.0

Eigen_PC

Pathogenic

0.83

FATHMM_MKL

Pathogenic

0.97

LIST_S2

Benign

0.0

.;.

MetaRNN

Benign

0.0

.;.

MutationAssessor

Benign

0.0

.;.

PhyloP100

6.6

PROVEAN

Benign

0.0

.;.

REVEL

Benign

0.0

Sift

Pathogenic

0.0

.;.

Sift4G

Pathogenic

0.0

.;.

Vest4

0.0

GERP RS

4.2

Mutation Taster

=1/99

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.93

SpliceAI score (max)

0.99

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.79

Position offset: 9

DS_AL_spliceai

0.99

Position offset: 1

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

Publications

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

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