16-172929-C-A

Variant names:

• chr16-172929-C-A
• rs281864803
• NM_000517.6:c.17C>A

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 0P and 1B. BP4

The NM_000517.6(HBA2):​c.17C>A​(p.Ala6Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. A6A) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 0)
• Consequence: HBA2 NM_000517.6 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -2.28
• Publications: 0 publications found

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]

HBA2 Gene-Disease associations (from GenCC):

• alpha thalassemia spectrum

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen
• erythrocytosis, familial, 7

  Inheritance: AD Classification: STRONG, LIMITED Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• 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
• Heinz body anemia

  Inheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)
• methemoglobinemia, alpha type

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen

ENSG00000294455 (HGNC:):

ACMG classification

Our verdict: Likely_benign. The variant received -1 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.29652822).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000517.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HBA2	NM_000517.6	MANE Select	c.17C>A	p.Ala6Asp	missense	Exon 1 of 3	NP_000508.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HBA2	ENST00000251595.11	TSL:1 MANE Select	c.17C>A	p.Ala6Asp	missense	Exon 1 of 3	ENSP00000251595.6
	HBA2	ENST00000482565.1	TSL:1	n.36C>A		non_coding_transcript_exon	Exon 1 of 2
	ENSG00000294455	ENST00000723700.1		n.229G>T		non_coding_transcript_exon	Exon 2 of 2

Frequencies

GnomAD3 genomes Cov.: 0

GnomAD4 exome Cov.: 0

GnomAD4 genome Cov.: 0

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Uncertain	0.073	D
BayesDel_noAF	Benign	-0.13
CADD	Benign	3.4
DANN	Benign	0.82
Eigen	Benign	-1.0
Eigen_PC	Benign	-1.0
FATHMM_MKL	Benign	0.014	N
M_CAP	Pathogenic	0.44	D
MetaRNN	Benign	0.30	T
MetaSVM	Benign	-0.39	T
PhyloP100		-2.3
PrimateAI	Uncertain	0.73	T
PROVEAN	Benign	-1.2	N
REVEL	Uncertain	0.53
Sift	Benign	0.46	T
Sift4G	Benign	0.62	T
Vest4		0.16
MutPred		0.11		Loss of MoRF binding (P = 0.0116)
MVP		0.99
MPC		1.8
ClinPred		0.087	T
GERP RS		1.7
PromoterAI		-0.090	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0
gMVP		0.71

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

Other links and lift over

dbSNP: rs281864803; hg19: chr16-222928;