7-76302978-G-C

Variant names:

• chr7-76302978-G-C
• rs1060503022
• NM_001540.5:c.266G>C

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM1 PM2 PP3

The NM_001540.5(HSPB1):​c.266G>C​(p.Arg89Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000144 in 1,391,544 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R89Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: HSPB1 NM_001540.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.17
• Publications: 0 publications found

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 13 uncertain in NM_001540.5
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.807

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HSPB1	NM_001540.5	c.266G>C	p.Arg89Pro	missense_variant	Exon 1 of 3	ENST00000248553.7	NP_001531.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HSPB1	ENST00000248553.7	c.266G>C	p.Arg89Pro	missense_variant	Exon 1 of 3	1	NM_001540.5	ENSP00000248553.6

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000144 AC: 2 AN: 1391544 Hom.: 0 Cov.: 31 AF XY: 0.00000145 AC XY: 1 AN XY: 687458

African (AFR) AF: 0.00 AC: 0 AN: 32106

American (AMR) AF: 0.00 AC: 0 AN: 36352

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25218

East Asian (EAS) AF: 0.00 AC: 0 AN: 36390

South Asian (SAS) AF: 0.00 AC: 0 AN: 80190

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 35414

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5638

European-Non Finnish (NFE) AF: 0.00000185 AC: 2 AN: 1082136

Other (OTH) AF: 0.00 AC: 0 AN: 58100

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.93
BayesDel_addAF	Uncertain	0.16	D
BayesDel_noAF	Uncertain	-0.010
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.91	D
Eigen	Uncertain	0.22
Eigen_PC	Benign	0.13
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Benign	0.76	T
M_CAP	Pathogenic	0.84	D
MetaRNN	Pathogenic	0.81	D
MetaSVM	Uncertain	0.60	D
MutationAssessor	Uncertain	2.2	M
PhyloP100		2.2
PrimateAI	Uncertain	0.64	T
PROVEAN	Uncertain	-3.4	D
REVEL	Pathogenic	0.71
Sift	Uncertain	0.0070	D
Sift4G	Benign	0.13	T
Polyphen		0.77	P
Vest4		0.47
MutPred		0.59		Loss of MoRF binding (P = 6e-04);
MVP		0.98
MPC		1.7
ClinPred		0.99	D
GERP RS		-0.39
PromoterAI		-0.066	Neutral
Varity_R		0.97
gMVP		0.90
Mutation Taster		=56/44	polymorphism

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

Other links and lift over

dbSNP: rs1060503022; hg19: chr7-75932295;