Genetic Variant HBA1:p.Pro38Leu (chr16-176946-C-T) – ACMG Classification: Likely_pathogenic (6 pts)

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1PP3_Strong

The NM_000558.5(HBA1):c.113C>T(p.Pro38Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P38R) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0 ( 0 hom., cov: 30)

Failed GnomAD Quality Control

Consequence

HBA1
NM_000558.5 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 1.20

Publications

6 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:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

PM1

In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 13 uncertain in NM_000558.5

PP3

MetaRNN computational evidence supports a deleterious effect, 0.986

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HBA1	NM_000558.5 link	c.113C>T	p.Pro38Leu	missense_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.113C>T	p.Pro38Leu	missense_variant	Exon 2 of 3	1	NM_000558.5	ENSP00000322421.5		P69905

Frequencies

GnomAD3 genomes

AF:

0.00

AC:

AN:

150062

Hom.:

Cov.:

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

Cov.:

GnomAD4 genome

Data not reliable, filtered out with message: AC0;AS_VQSR

AF:

0.00

AC:

AN:

150062

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

73194

African (AFR)

AF:

0.00

AC:

AN:

40490

American (AMR)

AF:

0.00

AC:

AN:

15100

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3458

East Asian (EAS)

AF:

0.00

AC:

AN:

5052

South Asian (SAS)

AF:

0.00

AC:

AN:

4632

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10470

Middle Eastern (MID)

AF:

0.00

AC:

AN:

314

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67616

Other (OTH)

AF:

0.00

AC:

AN:

2022

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.93

BayesDel_addAF

Pathogenic

0.52

BayesDel_noAF

Pathogenic

0.51

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.45

T;.

Eigen

Uncertain

0.35

Eigen_PC

Uncertain

0.39

FATHMM_MKL

Uncertain

0.97

LIST_S2

Uncertain

0.94

D;D

M_CAP

Pathogenic

0.97

MetaRNN

Pathogenic

0.99

D;D

MetaSVM

Pathogenic

1.1

PhyloP100

1.2

PrimateAI

Uncertain

0.63

PROVEAN

Pathogenic

-9.4

D;D

REVEL

Pathogenic

0.93

Sift

Pathogenic

0.0

D;D

Sift4G

Pathogenic

0.0

D;D

Vest4

0.58

MutPred

0.94

Loss of glycosylation at P38 (P = 0.0535);.;

MVP

1.0

ClinPred

1.0

GERP RS

4.5

PromoterAI

0.0065

Neutral

(source)

Varity_R

0.98

gMVP

0.96

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

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over