chr7-76302792-G-A

Position:

• chr7-76302792-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 6P and 4B. PM1 PP3_Strong BS2

The NM_001540.5(HSPB1):​c.80G>A​(p.Arg27His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000549 in 1,456,266 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 (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: HSPB1 NM_001540.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.10

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM1: In a chain Heat shock protein beta-1 (size 204) in uniprot entity HSPB1_HUMAN there are 34 pathogenic changes around while only 2 benign (94%) in NM_001540.5
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.963
• BS2: High AC in GnomAdExome4 at 8 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
HSPB1	NM_001540.5	c.80G>A	p.Arg27His	missense_variant	1/3	ENST00000248553.7	NP_001531.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
HSPB1	ENST00000248553.7	c.80G>A	p.Arg27His	missense_variant	1/3	1	NM_001540.5	ENSP00000248553	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.0000127 AC: 3 AN: 235340 Hom.: 0 AF XY: 0.00000768 AC XY: 1 AN XY: 130138

Gnomad AFR exome AF: 0.0000729

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000189

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000549 AC: 8 AN: 1456266 Hom.: 0 Cov.: 31 AF XY: 0.00000552 AC XY: 4 AN XY: 724558

Gnomad4 AFR exome AF: 0.00

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: 0.00000630

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000834 AC: 1

EpiCase AF: 0.0000545

EpiControl AF: 0.0000595

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Charcot-Marie-Tooth disease axonal type 2F Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 04, 2022

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. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt HSPB1 protein function. This variant has not been reported in the literature in individuals affected with HSPB1-related conditions. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 27 of the HSPB1 protein (p.Arg27His). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.30
BayesDel_addAF	Pathogenic	0.47	D
BayesDel_noAF	Pathogenic	0.46
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.86	D
Eigen	Uncertain	0.20
Eigen_PC	Uncertain	0.27
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.86	D
M_CAP	Pathogenic	0.77	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Uncertain	0.54	D
MutationAssessor	Uncertain	2.3	M
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.85	D
PROVEAN	Uncertain	-3.1	D
REVEL	Pathogenic	0.85
Sift	Uncertain	0.017	D
Sift4G	Uncertain	0.020	D
Polyphen		0.15	B
Vest4		0.91
MutPred		0.80		Gain of catalytic residue at D30 (P = 0.1277);
MVP		0.98
MPC		0.76
ClinPred		0.78	D
GERP RS		3.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.4
Varity_R		0.56
gMVP		0.91

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

LitVar

Other links and lift over

dbSNP: rs367662394; hg19: chr7-75932109;