rs34504387

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_000558.5(HBA1):​c.55G>A​(p.Gly19Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000133 in 150,064 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G19D) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 28)
Exomes 𝑓: 0.0000070 ( 0 hom. )
Failed GnomAD Quality Control

Consequence

HBA1
NM_000558.5 missense

Scores

3
6
9

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: -0.0530

Publications

7 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)

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2
Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
HBA1NM_000558.5 linkc.55G>A p.Gly19Ser missense_variant Exon 1 of 3 ENST00000320868.9 NP_000549.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
HBA1ENST00000320868.9 linkc.55G>A p.Gly19Ser missense_variant Exon 1 of 3 1 NM_000558.5 ENSP00000322421.5

Frequencies

GnomAD3 genomes
AF:
0.0000133
AC:
2
AN:
150064
Hom.:
0
Cov.:
28
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:
0.0000300
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.00000603
AC:
1
AN:
165754
AF XY:
0.00
show subpopulations
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:
0.0000152
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
Data not reliable, filtered out with message: AS_VQSR
AF:
0.00000696
AC:
10
AN:
1436054
Hom.:
0
Cov.:
27
AF XY:
0.00000280
AC XY:
2
AN XY:
713222
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:
0
AN:
32458
American (AMR)
AF:
0.00
AC:
0
AN:
41884
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
25752
East Asian (EAS)
AF:
0.00
AC:
0
AN:
38654
South Asian (SAS)
AF:
0.0000120
AC:
1
AN:
83062
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
51348
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
4352
European-Non Finnish (NFE)
AF:
0.00000819
AC:
9
AN:
1099248
Other (OTH)
AF:
0.00
AC:
0
AN:
59296
⚠️ 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: 0.260
Heterozygous variant carriers
0
1
3
4
6
7
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<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:
0.0000133
AC:
2
AN:
150064
Hom.:
0
Cov.:
28
AF XY:
0.0000274
AC XY:
2
AN XY:
73076
show subpopulations
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.00
AC:
0
AN:
41094
American (AMR)
AF:
0.00
AC:
0
AN:
15140
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3406
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5080
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4774
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10530
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
302
European-Non Finnish (NFE)
AF:
0.0000300
AC:
2
AN:
66776
Other (OTH)
AF:
0.00
AC:
0
AN:
2050
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 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: 0.250
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<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.:
0

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

not provided Uncertain:1
Oct 10, 2017
Quest Diagnostics Nichols Institute San Juan Capistrano
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.11
BayesDel_addAF
Pathogenic
0.19
D
BayesDel_noAF
Uncertain
0.040
CADD
Benign
18
DANN
Uncertain
0.98
DEOGEN2
Benign
0.12
T
Eigen
Benign
-0.29
Eigen_PC
Benign
-0.40
FATHMM_MKL
Benign
0.50
N
LIST_S2
Benign
0.78
T
M_CAP
Pathogenic
0.65
D
MetaRNN
Uncertain
0.46
T
MetaSVM
Uncertain
0.37
D
PhyloP100
-0.053
PrimateAI
Uncertain
0.56
T
PROVEAN
Benign
-1.8
N
REVEL
Uncertain
0.53
Sift
Pathogenic
0.0
D
Sift4G
Benign
1.0
T
Vest4
0.27
MVP
1.0
ClinPred
0.39
T
GERP RS
4.4
PromoterAI
0.011
Neutral
Varity_R
0.61
gMVP
0.67

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.090
Details are displayed if max score is > 0.2

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

Publications

Other links and lift over

dbSNP: rs34504387; hg19: chr16-226770; API