NM_001540.5:c.539C>T

Variant names:

• chr7-76304094-C-T
• rs1422978230
• NM_001540.5:c.539C>T

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PM1 PM2 PP5_Very_Strong

The NM_001540.5(HSPB1):​c.539C>T​(p.Thr180Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,474 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T180P) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: HSPB1 NM_001540.5 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3 U:1
• Conservation: PhyloP100: 2.00
• Publications: 11 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: Illumina, Labcorp Genetics (formerly Invitae), ClinGen, Orphanet
• 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: Pathogenic. The variant received 12 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 12 uncertain in NM_001540.5
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 7-76304094-C-T is Pathogenic according to our data. Variant chr7-76304094-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 447531.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001540.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HSPB1	NM_001540.5	MANE Select	c.539C>T	p.Thr180Ile	missense	Exon 3 of 3	NP_001531.1	P04792

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HSPB1	ENST00000248553.7	TSL:1 MANE Select	c.539C>T	p.Thr180Ile	missense	Exon 3 of 3	ENSP00000248553.6	P04792
	HSPB1	ENST00000429938.1	TSL:1	c.35C>T	p.Thr12Ile	missense	Exon 3 of 3	ENSP00000405285.1	C9J3N8
	HSPB1	ENST00000447574.1	TSL:1	n.1289C>T		non_coding_transcript_exon	Exon 2 of 2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461474 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 727000

African (AFR) AF: 0.0000299 AC: 1 AN: 33472

American (AMR) AF: 0.00 AC: 0 AN: 44692

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39684

South Asian (SAS) AF: 0.00 AC: 0 AN: 86204

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53302

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5734

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111894

Other (OTH) AF: 0.00 AC: 0 AN: 60362

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
2	-	-	Charcot-Marie-Tooth disease axonal type 2F (2)
-	1	-	Charcot-Marie-Tooth disease (1)
1	-	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.25
BayesDel_addAF	Pathogenic	0.39	D
BayesDel_noAF	Pathogenic	0.32
CADD	Benign	22
DANN	Benign	0.96
DEOGEN2	Pathogenic	0.80	D
Eigen	Benign	-0.22
Eigen_PC	Benign	-0.086
FATHMM_MKL	Uncertain	0.83	D
LIST_S2	Benign	0.81	T
M_CAP	Uncertain	0.16	D
MetaRNN	Uncertain	0.63	D
MetaSVM	Uncertain	0.38	D
MutationAssessor	Benign	1.5	L
PhyloP100		2.0
PrimateAI	Uncertain	0.71	T
PROVEAN	Benign	-2.3	N
REVEL	Uncertain	0.61
Sift	Benign	0.19	T
Sift4G	Benign	0.19	T
Polyphen		0.056	B
Vest4		0.61
MutPred		0.39		Loss of glycosylation at T180 (P = 0.0305)
MVP		0.99
MPC		1.5
ClinPred		0.90	D
GERP RS		4.7
Varity_R		0.51
gMVP		0.69
Mutation Taster		=21/79	disease causing (ClinVar)

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: rs1422978230; hg19: chr7-75933411;