14-24261773-C-G

Variant names:

• chr14-24261773-C-G
• rs778635368
• NM_000359.3:c.430G>C

Variant summary

Our verdict is Pathogenic. The variant received 21 ACMG points: 21P and 0B. PS1_Very_Strong PM1 PM2 PM5 PP2 PP3_Strong PP5_Moderate

The NM_000359.3(TGM1):​c.430G>C​(p.Gly144Arg) variant causes a missense change involving the alteration of a conserved nucleotide. 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 the same amino acid substitution has been previously reported as Likely pathogenic in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G144E) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TGM1 NM_000359.3 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.56
• Publications: 0 publications found

Genes affected

TGM1 (HGNC:11777): (transglutaminase 1) The protein encoded by this gene is a membrane protein that catalyzes the addition of an alkyl group from an akylamine to a glutamine residue of a protein, forming an alkylglutamine in the protein. This protein alkylation leads to crosslinking of proteins and catenation of polyamines to proteins. This gene contains either one or two copies of a 22 nt repeat unit in its 3' UTR. Mutations in this gene have been associated with autosomal recessive lamellar ichthyosis (LI) and nonbullous congenital ichthyosiform erythroderma (NCIE). [provided by RefSeq, Jul 2008]

TGM1 Gene-Disease associations (from GenCC):

• autosomal recessive congenital ichthyosis 1

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Myriad Women’s Health, PanelApp Australia, Genomics England PanelApp
• acral self-healing collodion baby

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• bathing suit ichthyosis

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• congenital non-bullous ichthyosiform erythroderma

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• lamellar ichthyosis

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• self-healing collodion baby

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 21 ACMG points.

• PS1: Transcript NM_000359.3 (TGM1) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.
• PM1: In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 5 uncertain in NM_000359.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr14-24261772-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 555239.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 81 curated pathogenic missense variants (we use a threshold of 10). The gene has 20 curated benign missense variants. Gene score misZ: -0.060191 (below the threshold of 3.09). Trascript score misZ: 1.7514 (below the threshold of 3.09). GenCC associations: The gene is linked to autosomal recessive congenital ichthyosis 1, acral self-healing collodion baby, bathing suit ichthyosis, congenital non-bullous ichthyosiform erythroderma, lamellar ichthyosis, self-healing collodion baby.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.996
• PP5: Variant 14-24261773-C-G is Pathogenic according to our data. Variant chr14-24261773-C-G is described in ClinVar as Pathogenic. ClinVar VariationId is 1413628.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TGM1	NM_000359.3	c.430G>C	p.Gly144Arg	missense_variant	Exon 3 of 15	ENST00000206765.11	NP_000350.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TGM1	ENST00000206765.11	c.430G>C	p.Gly144Arg	missense_variant	Exon 3 of 15	1	NM_000359.3	ENSP00000206765.6
TGM1	ENST00000544573.5	c.-29+354G>C		intron_variant	Intron 2 of 8	2		ENSP00000439446.1
TGM1	ENST00000558074.1	c.*25G>C		downstream_gene_variant		5		ENSP00000453840.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Aug 25, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt TGM1 protein function. This missense change has been observed in individual(s) with autosomal recessive congenital ichthyosis (PMID: 9545389, 21895619). In at least one individual the data is consistent with the variant being in trans (on the opposite chromosome) from a pathogenic variant. This variant is not present in population databases (ExAC no frequency). This sequence change replaces glycine with arginine at codon 144 of the TGM1 protein (p.Gly144Arg). The glycine residue is highly conserved and there is a moderate physicochemical difference between glycine and arginine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.55
CADD	Uncertain	25
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.97	D
Eigen	Pathogenic	0.75
Eigen_PC	Uncertain	0.63
FATHMM_MKL	Pathogenic	0.99	D
M_CAP	Pathogenic	0.63	D
MetaRNN	Pathogenic	1.0	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.1	M
PhyloP100		7.6
PrimateAI	Uncertain	0.64	T
PROVEAN	Pathogenic	-7.0	D
REVEL	Pathogenic	0.97
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.96
MutPred		0.99		Loss of sheet (P = 0.0817);
MVP		0.99
MPC		1.0
ClinPred		1.0	D
GERP RS		5.1
Varity_R		0.95
gMVP		0.92
Mutation Taster		=5/95	disease causing

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: rs778635368; hg19: chr14-24730979;