rs1057519637

chr16-173002-GGA-G

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1 PP5_Moderate

The NM_000517.6(HBA2):c.94_95del(p.Arg32AspfsTer25) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 3)
• Consequence: HBA2 NM_000517.6 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1 O:1
• Conservation: PhyloP100: 0.894

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]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 46 pathogenic variants in the truncated region.
• PP5: Variant 16-173002-GGA-G is Pathogenic according to our data. Variant chr16-173002-GGA-G is described in ClinVar as [Pathogenic]. Clinvar id is 375744.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
HBA2	NM_000517.6	c.94_95del	p.Arg32AspfsTer25	frameshift_variant	1/3	ENST00000251595.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
HBA2	ENST00000251595.11	c.94_95del	p.Arg32AspfsTer25	frameshift_variant	1/3	1	NM_000517.6	P1
HBA2	ENST00000484216.1	c.63_64del	p.Arg22AspfsTer25	frameshift_variant	1/2	1
HBA2	ENST00000482565.1	n.113_114del		non_coding_transcript_exon_variant	1/2	1
HBA2	ENST00000397806.1	c.-2+48_-2+49del		intron_variant		2

Frequencies

GnomAD3 genomes Cov.: 3

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 3

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Quest Diagnostics Nichols Institute San Juan Capistrano

Oct 25, 2018

This frameshift variant alters the translational reading frame of the mRNA and causes the premature termination of protein synthesis. The variant is found in at least one symptomatic individual, and not found in general population data. -

alpha Thalassemia Other:1

not provided, no classification provided

literature only

GeneReviews

-

- -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.10		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: rs1057519637; hg19: chr16-223001;