13-30461422-CTT-C

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PVS1_Strong PM2

The NM_002128.7(HMGB1):c.581_582del(p.Glu194GlyfsTer3) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 31)
• Consequence: HMGB1 NM_002128.7 frameshift
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.44

Genes affected

HMGB1 (HGNC:4983): (high mobility group box 1) This gene encodes a protein that belongs to the High Mobility Group-box superfamily. The encoded non-histone, nuclear DNA-binding protein regulates transcription, and is involved in organization of DNA. This protein plays a role in several cellular processes, including inflammation, cell differentiation and tumor cell migration. Multiple pseudogenes of this gene have been identified. Alternative splicing results in multiple transcript variants that encode the same protein. [provided by RefSeq, Sep 2015]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.103 CDS is truncated, and there are 0 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
HMGB1	NM_002128.7	c.581_582del	p.Glu194GlyfsTer3	frameshift_variant	5/5	ENST00000341423.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
HMGB1	ENST00000341423.10	c.581_582del	p.Glu194GlyfsTer3	frameshift_variant	5/5	1	NM_002128.7	P1

Frequencies

GnomAD3 genomes Cov.: 31

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

HMGB1-related Developmental delay and microcephaly Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

New York Genome Center

Feb 02, 2022

The de novo heterozygous frameshift variant (p.Glu194GlyfsTer3) identified in HMGB1 has not been reported in affected individuals in the literature. The variant is absent from the gnomAD database (v3) indicating it is an extremely rare allele in the general population. The p.Glu194GlyfsTer3 variant is located in the last exon (5/5) of the HMGB1 gene. The resulting mutant mRNA is predicted to escape nonsense mediated mRNA decay and removes more than 10% of transcript. Frameshift and stop-gained variants downstream of p.Glu194GlyfsTer3 have not been reported in the literature. Based on the available evidence, the de novo Glu194GlyfsTer3 variant identified in HMGB1 is assessed as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr13-31035559;