Genetic Variant HBA1:p.Asn79Asn (chr16-177070-C-T) – ACMG Classification: Likely_benign (-3 pts)

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2BP4_StrongBP7

The NM_000558.5(HBA1):c.237C>T(p.Asn79Asn) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000266 in 150,438 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 0.000027 ( 0 hom., cov: 31)

Exomes 𝑓: 0.000010 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

HBA1
NM_000558.5 synonymous

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: -5.08

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 links:

ENSG00000290010 (HGNC:):

ENSG00000290010 links:

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ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.76).

BP7

Synonymous conserved (PhyloP=-5.08 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HBA1	NM_000558.5 link	c.237C>T	p.Asn79Asn	synonymous_variant	Exon 2 of 3	ENST00000320868.9	NP_000549.1	P69905D1MGQ2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HBA1	ENST00000320868.9 link	c.237C>T	p.Asn79Asn	synonymous_variant	Exon 2 of 3	1	NM_000558.5	ENSP00000322421.5		P69905

Frequencies

GnomAD3 genomes

AF:

0.0000266

AC:

AN:

150438

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000731

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:

0.0000149

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000697

AC:

AN:

143526

Hom.:

AF XY:

0.00

AC XY:

AN XY:

78184

show subpopulations

Gnomad AFR exome

AF:

0.000131

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS 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:

0.0000102

AC:

AN:

1375496

Hom.:

Cov.:

AF XY:

0.00000440

AC XY:

AN XY:

681874

show subpopulations

Gnomad4 AFR exome

AF:

0.000189

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.000190

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

9.38e-7

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000266

AC:

AN:

150438

Hom.:

Cov.:

AF XY:

0.0000273

AC XY:

AN XY:

73296

show subpopulations

Gnomad4 AFR

AF:

0.0000731

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000149

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000340

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.76

CADD

Benign

1.2

DANN

Benign

0.92

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

LitVar

Other links and lift over