11-5226660-G-A

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1PM2PP3_Moderate

The NM_000518.5(HBB):​c.232C>T​(p.His78Tyr) 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 pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. H78D) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 32)
Exomes 𝑓: 6.8e-7 ( 0 hom. )
Failed GnomAD Quality Control

Consequence

HBB
NM_000518.5 missense

Scores

7
7
5

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3O:1

Conservation

PhyloP100: 0.993

Publications

16 publications found
Variant links:
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]
HBB Gene-Disease associations (from GenCC):
  • dominant beta-thalassemia
    Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), ClinGen
  • hemoglobin M disease
    Inheritance: AD Classification: DEFINITIVE, MODERATE, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics, ClinGen
  • beta thalassemia
    Inheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health
  • beta-thalassemia HBB/LCRB
    Inheritance: AR, SD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics
  • sickle cell disease and related diseases
    Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
  • erythrocytosis, familial, 6
    Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp
  • Heinz body anemia
    Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
  • sickle cell disease
    Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae)
  • hereditary persistence of fetal hemoglobin-beta-thalassemia syndrome
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • beta-thalassemia intermedia
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • beta-thalassemia major
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • delta-beta-thalassemia
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • hemoglobin C disease
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • hemoglobin C-beta-thalassemia syndrome
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • hemoglobin E disease
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • hemoglobin E-beta-thalassemia syndrome
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • hereditary persistence of fetal hemoglobin-sickle cell disease syndrome
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • sickle cell-beta-thalassemia disease syndrome
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • sickle cell-hemoglobin c disease syndrome
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • sickle cell-hemoglobin d disease syndrome
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • sickle cell-hemoglobin E disease syndrome
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

PM1
In a hotspot region, there are 9 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 4 benign, 37 uncertain in NM_000518.5
PM2
Very rare variant in population databases, with high coverage;
PP3
MetaRNN computational evidence supports a deleterious effect, 0.887

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
HBBNM_000518.5 linkc.232C>T p.His78Tyr missense_variant Exon 2 of 3 ENST00000335295.4 NP_000509.1 P68871D9YZU5

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
HBBENST00000335295.4 linkc.232C>T p.His78Tyr missense_variant Exon 2 of 3 1 NM_000518.5 ENSP00000333994.3 P68871

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD2 exomes
AF:
0.00000398
AC:
1
AN:
251428
AF XY:
0.00000736
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00000879
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
Data not reliable, filtered out with message: AS_VQSR
AF:
6.84e-7
AC:
1
AN:
1461870
Hom.:
0
Cov.:
36
AF XY:
0.00000138
AC XY:
1
AN XY:
727240
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33480
American (AMR)
AF:
0.00
AC:
0
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39700
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53418
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5766
European-Non Finnish (NFE)
AF:
8.99e-7
AC:
1
AN:
1111992
Other (OTH)
AF:
0.00
AC:
0
AN:
60396
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.525
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
Cov.:
32
Alfa
AF:
0.00
Hom.:
0
ExAC
AF:
0.00000824
AC:
1

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:3Other:1
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not specified Uncertain:1
Jul 25, 2022
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.232C>T (p.His78Tyr) also known as Hb-Fukuyama results in a conservative amino acid change located in the Globin domain (IPR000971) of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 251428 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.232C>T has been reported in the literature as a slightly unstable hemoglobin in reportedly unaffected individuals during routine HbA1c analysis (example, Landin_1993). These report(s) do not provide unequivocal conclusions about association of the variant with Hemoglobinopathy. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

beta Thalassemia Uncertain:1
Jul 08, 2020
Natera, Inc.
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

not provided Uncertain:1
Jul 25, 2019
ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The Hb Fukuyama variant (HBB: c.232C>T; p.His78Tyr, also known as His77Tyr when numbered from the mature protein, rs33991294) is reported in the literature in several heterozygous individuals without clinical symptoms (HbVar database and references therein). This variant is found on a single chromosome (1/251428 alleles) in the Genome Aggregation Database. The histidine at codon 78 is weakly conserved, but computational analyses (SIFT, PolyPhen-2) predict that this variant is deleterious, and functional assays suggest the variant is mildly unstable (HbVar database and references therein). However, due to limited information, the clinical significance of the Hb Fukuyama variant is uncertain at this time. References: HbVar link to Hb Fukuyama: http://globin.bx.psu.edu/cgi-bin/hbvar/query_vars3?mode=output&display_format=page&i=394 -

HEMOGLOBIN FUKUYAMA Other:1
Dec 12, 2017
OMIM
Significance:other
Review Status:no assertion criteria provided
Collection Method:literature only

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Uncertain
0.56
BayesDel_addAF
Pathogenic
0.38
D
BayesDel_noAF
Pathogenic
0.31
CADD
Benign
18
DANN
Uncertain
0.99
DEOGEN2
Benign
0.073
T;T;.;T
Eigen
Benign
0.038
Eigen_PC
Benign
-0.17
FATHMM_MKL
Benign
0.57
D
LIST_S2
Uncertain
0.96
.;D;D;D
M_CAP
Pathogenic
0.35
D
MetaRNN
Pathogenic
0.89
D;D;D;D
MetaSVM
Uncertain
0.46
D
MutationAssessor
Pathogenic
3.1
M;M;.;.
PhyloP100
0.99
PrimateAI
Uncertain
0.52
T
PROVEAN
Uncertain
-4.1
D;.;.;D
REVEL
Pathogenic
0.73
Sift
Pathogenic
0.0
D;.;.;D
Sift4G
Uncertain
0.019
D;.;.;.
Polyphen
0.99
D;D;.;.
Vest4
0.83
MutPred
0.73
Gain of ubiquitination at K83 (P = 0.0762);Gain of ubiquitination at K83 (P = 0.0762);Gain of ubiquitination at K83 (P = 0.0762);Gain of ubiquitination at K83 (P = 0.0762);
MVP
0.93
MPC
0.21
ClinPred
0.97
D
GERP RS
1.9
PromoterAI
-0.016
Neutral
Varity_R
0.67
gMVP
0.67
Mutation Taster
=20/80
disease causing

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

Publications

Other links and lift over

dbSNP: rs33991294; hg19: chr11-5247890; COSMIC: COSV104647177; COSMIC: COSV104647177; API