NM_000558.5:c.22A>G

Variant names:

• chr16-176738-A-G
• rs281864807
• NM_000558.5:c.22A>G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_000558.5(HBA1):​c.22A>G​(p.Lys8Glu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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 nucleotide change resulting in the same amino acid substitution has been previously reported as Likely benign in UniProt.

• Frequency:
  • Genomes: not found (cov: 28)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: HBA1 NM_000558.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.76

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.992

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HBA1	NM_000558.5	c.22A>G	p.Lys8Glu	missense_variant	Exon 1 of 3	ENST00000320868.9	NP_000549.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HBA1	ENST00000320868.9	c.22A>G	p.Lys8Glu	missense_variant	Exon 1 of 3	1	NM_000558.5	ENSP00000322421.5
HBA1	ENST00000472694.1	n.41A>G		non_coding_transcript_exon_variant	Exon 1 of 2	1
HBA1	ENST00000397797	c.-26A>G		5_prime_UTR_variant	Exon 1 of 3	2		ENSP00000380899.1
HBA1	ENST00000487791.1	n.-10A>G		upstream_gene_variant		1

Frequencies

GnomAD3 genomes Cov.: 28

GnomAD4 exome Data not reliable, filtered out with message: AC0;AS_VQSR AF: 0.00 AC: 0 AN: 1435290 Hom.: 0 Cov.: 28 AF XY: 0.00 AC XY: 0 AN XY: 712468

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 28

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.73
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.43
CADD	Benign	21
DANN	Uncertain	0.99
DEOGEN2	Benign	0.29	T
Eigen	Benign	-0.17
Eigen_PC	Benign	-0.25
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.88	D
M_CAP	Pathogenic	0.85	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Uncertain	0.69	D
PrimateAI	Uncertain	0.65	T
PROVEAN	Uncertain	-3.0	D
REVEL	Pathogenic	0.78
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Vest4		0.91
MutPred		0.98		Loss of MoRF binding (P = 0.001);
MVP		0.99
ClinPred		0.99	D
GERP RS		3.3
Varity_R		0.91
gMVP		0.93

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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

Other links and lift over

dbSNP: rs281864807; hg19: chr16-226737;