Genetic Variant HBA1:c.301-17C>T (chr16-177266-C-T) – ACMG Classification: Likely_benign (-4 pts)

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BP4_Strong

The NM_000558.5(HBA1):c.301-17C>T variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000372 in 1,613,156 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

HBA1
NM_000558.5 intron

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: -1.06

Publications

0 publications found

Variant links:

Genes affected

HBA1 (HGNC:4823): (hemoglobin subunit alpha 1) 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]

HBA1 Gene-Disease associations (from GenCC):

HBA1-related alpha thalassemia spectrum
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
alpha thalassemia spectrum
Inheritance: SD, AR Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
erythrocytosis, familial, 7
Inheritance: AD Classification: STRONG, MODERATE Submitted by: Genomics England PanelApp, ClinGen
unstable hemoglobin disease
Inheritance: AD Classification: MODERATE Submitted by: ClinGen
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
methemoglobinemia, alpha type
Inheritance: AD Classification: LIMITED Submitted by: ClinGen
Heinz body anemia
Inheritance: AR Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

HBA1 links:

ENSG00000294436 (HGNC:):

ENSG00000294436 links:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -4 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.79).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000558.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HBA1	NM_000558.5	MANE Select	c.301-17C>T		intron	N/A	NP_000549.1	P69905

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	Effect	Exon Rank	Protein	UniProt
HBA1	ENST00000320868.9	TSL:1 MANE Select	c.301-17C>T	intron	N/A	ENSP00000322421.5	P69905
HBA1	ENST00000487791.1	TSL:1	n.402C>T	non_coding_transcript_exon	Exon 2 of 2
HBA1	ENST00000472694.1	TSL:1	n.437-17C>T	intron	N/A

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152240

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:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000205

AC:

AN:

1460916

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

726790

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33474

American (AMR)

AF:

0.00

AC:

AN:

44706

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26112

East Asian (EAS)

AF:

0.00

AC:

AN:

39688

South Asian (SAS)

AF:

0.00

AC:

AN:

86226

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52688

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5758

European-Non Finnish (NFE)

AF:

0.00000270

AC:

AN:

1111904

Other (OTH)

AF:

0.00

AC:

AN:

60360

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152240

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74378

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41466

American (AMR)

AF:

0.00

AC:

AN:

15284

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5196

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000441

AC:

AN:

68048

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.492

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000113

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.79

CADD

Benign

0.30

(source)

DANN

Benign

0.73

PhyloP100

-1.1

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.0

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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over