rs1554614633

Variant names:

• chr7-76303809-CGAG-C
• rs1554614633
• NM_001540.5:c.376_378delGAG

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM1 PM2 PM4_Supporting

The NM_001540.5(HSPB1):​c.376_378delGAG​(p.Glu126del) variant causes a conservative inframe deletion change. The variant allele was found at a frequency of 0.00000206 in 1,458,708 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: HSPB1 NM_001540.5 conservative_inframe_deletion
• Clinical Significance: Uncertain significance criteria provided, single submitter U:2
• Conservation: PhyloP100: 5.21
• 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 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 20 uncertain in NM_001540.5
• PM2: Very rare variant in population databases, with high coverage
• PM4: Nonframeshift variant in NON repetitive region in NM_001540.5. Strenght limited to Supporting due to length of the change: 1aa.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HSPB1	NM_001540.5	c.376_378delGAG	p.Glu126del	conservative_inframe_deletion	Exon 2 of 3	ENST00000248553.7	NP_001531.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HSPB1	ENST00000248553.7	c.376_378delGAG	p.Glu126del	conservative_inframe_deletion	Exon 2 of 3	1	NM_001540.5	ENSP00000248553.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1458708 Hom.: 0 AF XY: 0.00000138 AC XY: 1 AN XY: 725664

African (AFR) AF: 0.00 AC: 0 AN: 33398

American (AMR) AF: 0.00 AC: 0 AN: 44708

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26124

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86160

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52624

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4200

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111620

Other (OTH) AF: 0.00 AC: 0 AN: 60176

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, single submitter

Submissions by phenotype

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

Jan 02, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant, c.376_378del, results in the deletion of 1 amino acid(s) of the HSPB1 protein (p.Glu126del), but otherwise preserves the integrity of the reading frame. This variant is not present in population databases (gnomAD no frequency). 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: 465274). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. 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. -

not provided Uncertain:1

-

Inherited Neuropathy Consortium

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: provider interpretation

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		5.2

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: rs1554614633; hg19: chr7-75933126;