ENST00000647020.1:c.-82C>A

Variant names:

• chr11-5227103-G-T
• rs34500389
• ENST00000647020.1:c.-82C>A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The ENST00000647020.1(HBB):​c.-82C>A variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000122 in 821,440 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000012 (0 hom.)
• Consequence: HBB ENST00000647020.1 5_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter P:2 U:1
• Conservation: PhyloP100: 0.522

Genes affected

HBB (HGNC:4827): (hemoglobin subunit beta) The alpha (HBA) and beta (HBB) loci determine the structure of the 2 types of polypeptide chains in adult hemoglobin, Hb A. The normal adult hemoglobin tetramer consists of two alpha chains and two beta chains. Mutant beta globin causes sickle cell anemia. Absence of beta chain causes beta-zero-thalassemia. Reduced amounts of detectable beta globin causes beta-plus-thalassemia. The order of the genes in the beta-globin cluster is 5'-epsilon -- gamma-G -- gamma-A -- delta -- beta--3'. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.31).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HBB	NM_000518.5	c.-82C>A		upstream_gene_variant		ENST00000335295.4	NP_000509.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HBB	ENST00000335295.4	c.-82C>A		upstream_gene_variant		1	NM_000518.5	ENSP00000333994.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000122 AC: 1 AN: 821440 Hom.: 0 Cov.: 11 AF XY: 0.00 AC XY: 0 AN XY: 432430

Gnomad4 AFR exome AF: 0.0000475

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.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

beta Thalassemia Pathogenic:1

Nov 25, 2019

The ITHANET community portal, The Cyprus Institute of Neurology and Genetics

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: curation

- -

Beta-plus-thalassemia Pathogenic:1

Jan 01, 1992

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

not specified Uncertain:1

Feb 16, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: HBB c.-82C>A affects a non-conserved nucleotide that is located in the untranscribed region, one nucleotide upstream to the conserved ATAAA sequence (i.e. the TATA box) therefore, it could affect gene expression. A saturation mutagenesis study reported that this variant had no significant effect on gene expression (Kircher_2019). The variant was absent in 31390 control chromosomes (gnomAD). c.-82C>A has been reported in the literature in at-least one individual with features of Beta Thalassemia (example: Lin_1992). These data indicate that the variant may be associated with disease. One submitter provided clinical-significance assessments for this variant to ClinVar after 2014 and classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.31
CADD	Benign	15
DANN	Benign	0.87

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs34500389; hg19: chr11-5248333;