16-176675-C-T

Variant names:

Variant summary

Our verdict is Benign. The variant received -16 ACMG points: 0P and 16B. BP4_StrongBP6_Very_StrongBS2

The NM_000558.5(HBA1):c.-42C>T variant causes a upstream gene change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0102 in 152,062 control chromosomes in the GnomAD database, including 15 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.010 ( 15 hom., cov: 29)

Exomes 𝑓: 0.00095 ( 9 hom. )

Failed GnomAD Quality Control

Consequence

HBA1
NM_000558.5 upstream_gene

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:3

Conservation

PhyloP100: -2.77

Publications

2 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):

alpha thalassemia spectrum
Inheritance: AR, SD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
erythrocytosis, familial, 7
Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
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:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -16 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.75).

BP6

Variant 16-176675-C-T is Benign according to our data. Variant chr16-176675-C-T is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 439102.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BS2

High Homozygotes in GnomAd4 at 15 AR,AD,SD gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HBA1	NM_000558.5 link	c.-42C>T		upstream_gene_variant		ENST00000320868.9	NP_000549.1	P69905D1MGQ2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HBA1	ENST00000320868.9 link	c.-42C>T		upstream_gene_variant		1	NM_000558.5	ENSP00000322421.5		P69905

Frequencies

GnomAD3 genomes

AF:

0.0102

AC:

1551

AN:

151944

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0361

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00353

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:

0.0000147

Gnomad OTH

AF:

0.00574

GnomAD2 exomes

AF:

0.00236

AC:

580

AN:

245470

AF XY:

0.00179

show subpopulations

Gnomad AFR exome

AF:

0.0347

Gnomad AMR exome

AF:

0.00114

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000906

Gnomad OTH exome

AF:

0.000666

GnomAD4 exome

Data not reliable, filtered out with message: AS_VQSR

AF:

0.000952

AC:

1389

AN:

1458476

Hom.:

Cov.:

AF XY:

0.000813

AC XY:

590

AN XY:

725496

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.0345

AC:

1139

AN:

33046

American (AMR)

AF:

0.00167

AC:

AN:

44284

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26064

East Asian (EAS)

AF:

0.00

AC:

AN:

39590

South Asian (SAS)

AF:

0.0000931

AC:

AN:

85934

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53052

Middle Eastern (MID)

AF:

0.000743

AC:

AN:

5386

European-Non Finnish (NFE)

AF:

0.0000333

AC:

AN:

1110904

Other (OTH)

AF:

0.00211

AC:

127

AN:

60216

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.335

Heterozygous variant carriers

159

238

318

397

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

114

152

190

<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

AF:

0.0102

AC:

1554

AN:

152062

Hom.:

Cov.:

AF XY:

0.00987

AC XY:

734

AN XY:

74380

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.0360

AC:

1487

AN:

41260

American (AMR)

AF:

0.00353

AC:

AN:

15304

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:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10630

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68048

Other (OTH)

AF:

0.00568

AC:

AN:

2112

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.337

Heterozygous variant carriers

166

248

331

414

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Genome Hom

Variant carriers

100

<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:

0.000359

Hom.:

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Benign:2

Mar 17, 2020

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Apr 08, 2022

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

alpha Thalassemia

Benign:1

Sep 16, 2020

Natera, Inc.

Significance:Benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.75

CADD

Benign

5.1

(source)

DANN

Benign

0.80

PhyloP100

-2.8

PromoterAI

0.057

Neutral

(source)

Splicing

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

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over