rs34863047

Variant names:

• chr16-177316-G-A
• rs34863047
• NM_000558.5:c.334G>A

Your query was ambiguous. Multiple possible variants found:

• chr16-177316-G-A
• chr16-177316-G-T

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 4P and 1B. PM1 PM2 BP4

The NM_000558.5(HBA1):​c.334G>A​(p.Ala112Thr) 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 benign outcome for this variant. Variant has been reported in ClinVar as other (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A112V) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: HBA1 NM_000558.5 missense
• Clinical Significance: other no assertion criteria provided O:1
• Conservation: PhyloP100: -3.84
• Publications: 1 publications found

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):

• HBA1-related alpha thalassemia spectrum

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• alpha thalassemia spectrum

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

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Genomics England PanelApp, ClinGen
• unstable hemoglobin disease

  Inheritance: AD Classification: MODERATE Submitted by: ClinGen
• 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)

ENSG00000294436 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 15 uncertain in NM_000558.5
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.29654223).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000558.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HBA1	NM_000558.5	MANE Select	c.334G>A	p.Ala112Thr	missense	Exon 3 of 3	NP_000549.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HBA1	ENST00000320868.9	TSL:1 MANE Select	c.334G>A	p.Ala112Thr	missense	Exon 3 of 3	ENSP00000322421.5
	HBA1	ENST00000472694.1	TSL:1	n.470G>A		non_coding_transcript_exon	Exon 2 of 2
	HBA1	ENST00000397797.1	TSL:2	c.238G>A	p.Ala80Thr	missense	Exon 3 of 3	ENSP00000380899.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0;AS_VQSR AF: 0.00 AC: 0 AN: 1460802 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 726694

African (AFR) AF: 0.00 AC: 0 AN: 33474

American (AMR) AF: 0.00 AC: 0 AN: 44670

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26090

East Asian (EAS) AF: 0.00 AC: 0 AN: 39658

South Asian (SAS) AF: 0.00 AC: 0 AN: 86180

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52858

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111778

Other (OTH) AF: 0.00 AC: 0 AN: 60328

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions as Germline

Significance: other

Revision: no assertion criteria provided

Pathogenic	VUS	Benign	Condition
-	-	-	HEMOGLOBIN MOSELLA (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.068
BayesDel_addAF	Uncertain	0.14	D
BayesDel_noAF	Uncertain	-0.030
CADD	Benign	0.16
DANN	Benign	0.86
DEOGEN2	Benign	0.20	T
Eigen	Benign	-1.6
Eigen_PC	Benign	-1.8
FATHMM_MKL	Benign	0.015	N
LIST_S2	Uncertain	0.88	D
M_CAP	Uncertain	0.25	D
MetaRNN	Benign	0.30	T
MetaSVM	Benign	-0.42	T
PhyloP100		-3.8
PrimateAI	Benign	0.30	T
PROVEAN	Benign	-0.60	N
REVEL	Uncertain	0.53
Sift	Benign	0.12	T
Sift4G	Benign	0.56	T
Vest4		0.066
MutPred		0.60		Gain of glycosylation at A112 (P = 0.0136)
MVP		0.99
ClinPred		0.12	T
GERP RS		-8.9
Varity_R		0.24
gMVP		0.66

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: rs34863047; hg19: chr16-227315; COSMIC: COSV109408735; COSMIC: COSV109408735;