chr14-24261827-G-A
Variant summary
Our verdict is Pathogenic. The variant received 15 ACMG points: 15P and 0B. PM2PM5PP2PP3_ModeratePP5_Very_Strong
The NM_000359.3(TGM1):c.376C>T(p.Arg126Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000366 in 1,613,932 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 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. R126H) has been classified as Pathogenic.
Frequency
Consequence
NM_000359.3 missense
Scores
Clinical Significance
Conservation
Publications
- autosomal recessive congenital ichthyosis 1Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Myriad Women’s Health, PanelApp Australia, Genomics England PanelApp
- acral self-healing collodion babyInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- bathing suit ichthyosisInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- congenital non-bullous ichthyosiform erythrodermaInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- lamellar ichthyosisInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- self-healing collodion babyInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Pathogenic. The variant received 15 ACMG points.
Transcripts
RefSeq
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| TGM1 | ENST00000206765.11 | c.376C>T | p.Arg126Cys | missense_variant | Exon 3 of 15 | 1 | NM_000359.3 | ENSP00000206765.6 | ||
| TGM1 | ENST00000558074.1 | c.376C>T | p.Arg126Cys | missense_variant | Exon 4 of 4 | 5 | ENSP00000453840.1 | |||
| TGM1 | ENST00000544573.5 | c.-29+300C>T | intron_variant | Intron 2 of 8 | 2 | ENSP00000439446.1 |
Frequencies
GnomAD3 genomes AF: 0.0000526 AC: 8AN: 152134Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000279 AC: 7AN: 251168 AF XY: 0.0000221 show subpopulations
GnomAD4 exome AF: 0.0000349 AC: 51AN: 1461798Hom.: 0 Cov.: 32 AF XY: 0.0000289 AC XY: 21AN XY: 727206 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000526 AC: 8AN: 152134Hom.: 0 Cov.: 32 AF XY: 0.0000538 AC XY: 4AN XY: 74320 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Autosomal recessive congenital ichthyosis 1 Pathogenic:4Uncertain:1
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This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -
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not provided Pathogenic:2
The TGM1 p.R126C variant was identified as a compound heterozygous variant in 3 of 164 proband chromosomes (frequency: 0.0183) from individuals with Autosomal Recessive Congenital Ichthyosis (Herman_2009_PMID:19241467; Borsk√°_2019_PMID:31046801; Oji_2006_PMID:16968736). The variant was identified in dbSNP (ID: rs397514524) and ClinVar (classified as uncertain significance by Counsyl for Autosomal recessive congenital ichthyosis 1). The variant was identified in control databases in 7 of 251168 chromosomes at a frequency of 0.00002787 (Genome Aggregation Database March 6, 2019, v2.1.1). The variant was observed in the following populations: Other in 1 of 6126 chromosomes (freq: 0.000163), African in 1 of 16206 chromosomes (freq: 0.000062), European (Finnish) in 1 of 21594 chromosomes (freq: 0.000046) and European (non-Finnish) in 4 of 113590 chromosomes (freq: 0.000035), but was not observed in the Latino, Ashkenazi Jewish, East Asian, or South Asian populations. The p.R126 residue is conserved in mammals but not in more distantly related organisms, and computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) suggest that the variant may impact the protein. The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) do not predict a difference in splicing. This variant showed reduced expression and reduced relative TGase-1 protein activity compared to the wild-type (Oji_2006_PMID:16968736; Aufenvenne_2009_PMID:19212342). In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time although we would lean towards a more pathogenic role for this variant. This variant is classified as likely pathogenic. -
This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 126 of the TGM1 protein (p.Arg126Cys). This variant is present in population databases (rs397514524, gnomAD 0.007%). This missense change has been observed in individuals with congenital ichthyosis (PMID: 16968736, 19241467). ClinVar contains an entry for this variant (Variation ID: 39528). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt TGM1 protein function with a positive predictive value of 80%. Experimental studies have shown that this missense change affects TGM1 function (PMID: 19212342). This variant disrupts the p.Arg126 amino acid residue in TGM1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 19241467, 22437313, 31046801, 31168818). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at