16-173508-C-G

Position:

• chr16-173508-C-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_000517.6(HBA2):​c.337C>G​(p.His113Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000686 in 1,458,486 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 25)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: HBA2 NM_000517.6 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.150

Genes affected

HBA2 (HGNC:4824): (hemoglobin subunit alpha 2) 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]

ENSG00000290038 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.938

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
HBA2	NM_000517.6	c.337C>G	p.His113Asp	missense_variant	3/3	ENST00000251595.11	NP_000508.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
HBA2	ENST00000251595.11	c.337C>G	p.His113Asp	missense_variant	3/3	1	NM_000517.6	ENSP00000251595.6

Frequencies

GnomAD3 genomes Cov.: 25

GnomAD4 exome AF: 6.86e-7 AC: 1 AN: 1458486 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 725332

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 25

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.28	D
BayesDel_noAF	Pathogenic	0.16
CADD	Benign	20
DANN	Benign	0.94
DEOGEN2	Benign	0.19	.;T
Eigen	Benign	-0.11
Eigen_PC	Benign	-0.38
FATHMM_MKL	Benign	0.21	N
M_CAP	Pathogenic	0.62	D
MetaRNN	Pathogenic	0.94	D;D
MetaSVM	Uncertain	0.51	D
PrimateAI	Benign	0.46	T
PROVEAN	Pathogenic	-8.0	D;D
REVEL	Uncertain	0.57
Sift	Pathogenic	0.0	D;D
Sift4G	Uncertain	0.029	D;D
Vest4		0.48
MutPred		0.80		Loss of helix (P = 0.1299);.;
MVP		1.0
MPC		2.2
ClinPred		0.99	D
GERP RS		2.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		3.1
gMVP		0.91

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

Other links and lift over

dbSNP: rs281864885; hg19: chr16-223507;