12-119187080-G-T

Position:

• chr12-119187080-G-T

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PS1 PM1 PM2 PM5 PP3_Strong PP5_Moderate

The NM_014365.3(HSPB8):​c.423G>T​(p.Lys141Asn) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Another nucleotide change resulting in same amino acid change has been previously reported as Pathogenicin Lovd. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. K141E) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: HSPB8 NM_014365.3 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:2 U:1
• Conservation: PhyloP100: 7.14

Genes affected

HSPB8 (HGNC:30171): (heat shock protein family B (small) member 8) The protein encoded by this gene belongs to the superfamily of small heat-shock proteins containing a conservative alpha-crystallin domain at the C-terminal part of the molecule. The expression of this gene in induced by estrogen in estrogen receptor-positive breast cancer cells, and this protein also functions as a chaperone in association with Bag3, a stimulator of macroautophagy. Thus, this gene appears to be involved in regulation of cell proliferation, apoptosis, and carcinogenesis, and mutations in this gene have been associated with different neuromuscular diseases, including Charcot-Marie-Tooth disease. [provided by RefSeq, Jul 2008]

HSPB8 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 16 ACMG points.

• PS1: Transcript NM_014365.3 (HSPB8) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in Lovd
• PM1: In a chain Heat shock protein beta-8 (size 195) in uniprot entity HSPB8_HUMAN there are 7 pathogenic changes around while only 0 benign (100%) in NM_014365.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr12-119187078-A-G is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.948
• PP5: Variant 12-119187080-G-T is Pathogenic according to our data. Variant chr12-119187080-G-T is described in ClinVar as [Pathogenic]. Clinvar id is 2619.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr12-119187080-G-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
HSPB8	NM_014365.3	c.423G>T	p.Lys141Asn	missense_variant	2/3	ENST00000281938.7	NP_055180.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
HSPB8	ENST00000281938.7	c.423G>T	p.Lys141Asn	missense_variant	2/3	1	NM_014365.3	ENSP00000281938.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Athena Diagnostics

Apr 06, 2022

This variant has not been reported in large, multi-ethnic general populations (http://gnomad.broadinstitute.org). This variant segregates with Charcot-Marie-Tooth disease in at least one family. Assessment of experimental evidence suggests this variant results in abnormal protein function. Knock-in mice displayed a phenotype similar to Charcot-Marie-Tooth disease (PMID: 25206829, 28780615). Additionally, motor neurons expressing this variant exhibited neurite degeneration (PMID: 20538880). Further studies also showed that this variant leads to decreased binding to BAG3 (PMID: 20858900), but increased binding to HSPB1 and the formation of intracellular aggregates (PMID: 15122253, 20157854). -

Charcot-Marie-Tooth disease axonal type 2L Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Feb 01, 2005

- -

Charcot-Marie-Tooth disease Uncertain:1

Uncertain significance, no assertion criteria provided

literature only

Inherited Neuropathy Consortium

-

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.27	D
BayesDel_noAF	Pathogenic	0.15
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.91	D
Eigen	Uncertain	0.53
Eigen_PC	Uncertain	0.60
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.92	D
M_CAP	Uncertain	0.17	D
MetaRNN	Pathogenic	0.95	D
MetaSVM	Benign	-0.41	T
MutationAssessor	Uncertain	2.6	M
PrimateAI	Uncertain	0.78	T
PROVEAN	Uncertain	-2.6	D
REVEL	Pathogenic	0.77
Sift	Uncertain	0.0020	D
Sift4G	Uncertain	0.0040	D
Polyphen		1.0	D
Vest4		0.99
MutPred		0.80		Gain of catalytic residue at K137 (P = 0.0117);
MVP		1.0
MPC		0.94
ClinPred		0.97	D
GERP RS		5.7
Varity_R		0.85
gMVP		0.81

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: rs104894345; hg19: chr12-119624885;