7-76302715-G-A

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PVS1PM2PP5

The NM_001540.5(HSPB1):​c.3G>A​(p.Met1?) variant causes a start lost change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000025 in 1,601,518 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 Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 33)
Exomes 𝑓: 6.9e-7 ( 0 hom. )

Consequence

HSPB1
NM_001540.5 start_lost

Scores

11
3
2

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:1

Conservation

PhyloP100: 7.31

Publications

0 publications found
Variant links:
Genes affected
HSPB1 (HGNC:5246): (heat shock protein family B (small) member 1) This gene encodes a member of the small heat shock protein (HSP20) family of proteins. In response to environmental stress, the encoded protein translocates from the cytoplasm to the nucleus and functions as a molecular chaperone that promotes the correct folding of other proteins. This protein plays an important role in the differentiation of a wide variety of cell types. Expression of this gene is correlated with poor clinical outcome in multiple human cancers, and the encoded protein may promote cancer cell proliferation and metastasis, while protecting cancer cells from apoptosis. Mutations in this gene have been identified in human patients with Charcot-Marie-Tooth disease and distal hereditary motor neuropathy. [provided by RefSeq, Aug 2017]
HSPB1 Gene-Disease associations (from GenCC):
  • Charcot-Marie-Tooth disease axonal type 2F
    Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, ClinGen, Illumina, Labcorp Genetics (formerly Invitae)
  • neuronopathy, distal hereditary motor, type 2B
    Inheritance: AD Classification: MODERATE Submitted by: Ambry Genetics
  • distal hereditary motor neuropathy type 2
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 11 ACMG points.

PVS1
Start lost variant, next in-frame start position is after 36 pathogenic variants. Next in-frame start position is after 169 codons. Genomic position: 76304060. Lost 0.817 part of the original CDS.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 7-76302715-G-A is Pathogenic according to our data. Variant chr7-76302715-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 934124.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Likely_pathogenic=1}.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
HSPB1NM_001540.5 linkc.3G>A p.Met1? start_lost Exon 1 of 3 ENST00000248553.7 NP_001531.1 P04792V9HW43

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
HSPB1ENST00000248553.7 linkc.3G>A p.Met1? start_lost Exon 1 of 3 1 NM_001540.5 ENSP00000248553.6 P04792

Frequencies

GnomAD3 genomes
AF:
0.0000197
AC:
3
AN:
152216
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000441
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.00
AC:
0
AN:
235556
AF XY:
0.00
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:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
6.90e-7
AC:
1
AN:
1449302
Hom.:
0
Cov.:
31
AF XY:
0.00000139
AC XY:
1
AN XY:
721464
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33428
American (AMR)
AF:
0.00
AC:
0
AN:
44706
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26114
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39686
South Asian (SAS)
AF:
0.0000116
AC:
1
AN:
86148
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
42584
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
4616
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1111842
Other (OTH)
AF:
0.00
AC:
0
AN:
60178
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.425
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
AF:
0.0000197
AC:
3
AN:
152216
Hom.:
0
Cov.:
33
AF XY:
0.0000403
AC XY:
3
AN XY:
74364
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41456
American (AMR)
AF:
0.00
AC:
0
AN:
15282
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5186
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4836
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10626
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000441
AC:
3
AN:
68036
Other (OTH)
AF:
0.00
AC:
0
AN:
2094
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.00
Hom.:
0
Bravo
AF:
0.0000113
EpiCase
AF:
0.0000545
EpiControl
AF:
0.00

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:1Uncertain:1
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Inborn genetic diseases Pathogenic:1
Dec 11, 2019
Ambry Genetics
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The p.M1? variant (also known as c.3G>A) is located in coding exon 1 of the HSPB1 gene and results from a G to A substitution at nucleotide position 3. This alters the methionine residue at the initiation codon. There is an in-frame methionine 169 amino acids downstream from this initiation site which, if used, may result in an N-terminal truncation impacting the alpha-crystallin domain of HSPB1 which is thought to be crucial for the overall structure of small heat shock proteins; however, direct evidence is unavailable (Benndorf R et al. Mutat Res Rev Mutat Res 2014 pii: S1383-5742(14)00018-0). Since sequence variations that modify the initiation codon (ATG) are expected to result in either loss of translation initiation, N-terminal truncation, or cause a shift in the mRNA reading frame, this alteration is interpreted as likely pathogenic. -

Charcot-Marie-Tooth disease axonal type 2F Uncertain:1
Jul 30, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change affects the initiator methionine of the HSPB1 mRNA. The next in-frame methionine is located at codon 169. This variant is present in population databases (no rsID available, gnomAD 0.0008%). This variant has not been reported in the literature in individuals affected with HSPB1-related conditions. ClinVar contains an entry for this variant (Variation ID: 934124). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.60
D
BayesDel_noAF
Pathogenic
0.45
CADD
Uncertain
26
DANN
Uncertain
1.0
DEOGEN2
Uncertain
0.59
D
Eigen
Pathogenic
0.71
Eigen_PC
Pathogenic
0.70
FATHMM_MKL
Pathogenic
0.98
D
LIST_S2
Uncertain
0.90
D
M_CAP
Pathogenic
0.78
D
MetaRNN
Pathogenic
0.99
D
MetaSVM
Pathogenic
0.88
D
PhyloP100
7.3
PROVEAN
Benign
-1.6
N
REVEL
Pathogenic
0.85
Sift
Pathogenic
0.0
D
Sift4G
Pathogenic
0.0
D
Polyphen
1.0
D
Vest4
0.83
MutPred
0.99
Gain of catalytic residue at M1 (P = 0.0143);
MVP
0.99
ClinPred
1.0
D
GERP RS
4.9
PromoterAI
-0.16
Neutral
Varity_R
0.98
gMVP
0.82
Mutation Taster
=15/185
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: rs1173242313; hg19: chr7-75932032; API