rs33918778
Variant summary
Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1PM2PP3_Strong
The NM_000518.5(HBB):c.123G>T(p.Arg41Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,142 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R41K) has been classified as Likely benign.
Frequency
Consequence
NM_000518.5 missense
Scores
Clinical Significance
Conservation
Publications
- dominant beta-thalassemiaInheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), ClinGen
- hemoglobin M diseaseInheritance: AD Classification: DEFINITIVE, MODERATE, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics, ClinGen
- beta thalassemiaInheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health
- beta-thalassemia HBB/LCRBInheritance: AR, SD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics
- sickle cell disease and related diseasesInheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
- erythrocytosis, familial, 6Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp
- Heinz body anemiaInheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
- sickle cell diseaseInheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae)
- hereditary persistence of fetal hemoglobin-beta-thalassemia syndromeInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- beta-thalassemia intermediaInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- beta-thalassemia majorInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- delta-beta-thalassemiaInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- hemoglobin C diseaseInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- hemoglobin C-beta-thalassemia syndromeInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- hemoglobin E diseaseInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- hemoglobin E-beta-thalassemia syndromeInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- hereditary persistence of fetal hemoglobin-sickle cell disease syndromeInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- sickle cell-beta-thalassemia disease syndromeInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- sickle cell-hemoglobin c disease syndromeInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- sickle cell-hemoglobin d disease syndromeInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- sickle cell-hemoglobin E disease syndromeInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Likely_pathogenic. The variant received 8 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| HBB | NM_000518.5 | c.123G>T | p.Arg41Ser | missense_variant | Exon 2 of 3 | ENST00000335295.4 | NP_000509.1 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| HBB | ENST00000335295.4 | c.123G>T | p.Arg41Ser | missense_variant | Exon 2 of 3 | 1 | NM_000518.5 | ENSP00000333994.3 |
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152142Hom.: 0 Cov.: 32 show subpopulations
GnomAD4 exome Cov.: 36
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152142Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0AN XY: 74320 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Uncertain:2
The Hb Austin variant (HBB: c.123G>T; p.Arg41Ser, also known as Arg40Ser when numbered from the mature protein, rs33918778, HbVar ID: 311, ClinVar Variation ID: 439134) is reported in the literature in the heterozygous state in multiple individuals of Mexican ancestry with no clinical symptoms (HbVar and references therein, Racsa 2014, Moo-Penn 1977). However, the phenotype of this variant in the presence of other alpha globin variants is unknown. Functional characterization indicate that the variant hemoglobin has normal Bohr effect, increased oxygen affinity, reduced cooperativity, and found to dissociate into oxyHb dimers (HbVar and references therein). This variant is absent from the Genome Aggregation Database (v2.1.1), indicating it is not a common polymorphism. Computational analyses predict that this variant is deleterious (REVEL: 0.9). Due to the limited information regarding this variant, its clinical significance is uncertain at this time. References: Link to HbVar database: https://globin.bx.psu.edu/hbvar/menu.html Moo-Penn WF et al. Hemoglobins Austin and Waco: two hemoglobins with substitutions in the alpha 1 beta 2 contact region. Arch Biochem Biophys. 1977 Feb;179(1):86-94. doi: 10.1016/0003-9861(77)90089-3. PMID: 14597. Racsa LD et al. Beta-Globin gene sequencing of hemoglobin Austin revises the historically reported electrophoretic migration pattern. Arch Pathol Lab Med. 2014 Jun;138(6):819-22. PMID: 24878022. -
The HBB c.123G>T (p.Arg41Ser) variant (also known as Hb Austin) has been reported in the published literature to have normal stability and increased oxygen affinity, and individuals heterozygous for this variant have a normal clinical presentation (HbVar (http://globin.cse.psu.edu/cgi-bin/hbvar/counter) and PMID: 24878022 (2014)). Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded predictions that this variant is damaging. Based on the available information, we are unable to determine the clinical significance of this variant. -
beta Thalassemia Uncertain:1
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alpha Thalassemia;C0002895:Hb SS disease;C0019025:Hereditary persistence of fetal hemoglobin;C0700299:Heinz body anemia;C1840779:METHEMOGLOBINEMIA, BETA TYPE;C1858990:Dominant beta-thalassemia;C1970028:Malaria, susceptibility to;C4693822:Erythrocytosis, familial, 6;CN322236:Beta-thalassemia HBB/LCRB Uncertain:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at