NM_000303.3:c.710C>T
Variant summary
Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1PM2PM5PP3_StrongPP5_Very_Strong
The NM_000303.3(PMM2):c.710C>T(p.Thr237Met) variant causes a missense change. The variant allele was found at a frequency of 0.0000198 in 1,613,470 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. T237K) has been classified as Pathogenic.
Frequency
Consequence
NM_000303.3 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 18 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
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PMM2 | NM_000303.3 | c.710C>T | p.Thr237Met | missense_variant | Exon 8 of 8 | ENST00000268261.9 | NP_000294.1 | |
PMM2 | XM_047434215.1 | c.461C>T | p.Thr154Met | missense_variant | Exon 6 of 6 | XP_047290171.1 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000526 AC: 8AN: 152194Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000438 AC: 11AN: 251084Hom.: 0 AF XY: 0.0000516 AC XY: 7AN XY: 135728
GnomAD4 exome AF: 0.0000164 AC: 24AN: 1461276Hom.: 0 Cov.: 30 AF XY: 0.0000165 AC XY: 12AN XY: 726976
GnomAD4 genome AF: 0.0000526 AC: 8AN: 152194Hom.: 0 Cov.: 32 AF XY: 0.0000672 AC XY: 5AN XY: 74350
ClinVar
Submissions by phenotype
PMM2-congenital disorder of glycosylation Pathogenic:9Other:1
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Variant summary: PMM2 c.710C>T (p.Thr237Met) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4.4e-05 in 251084 control chromosomes. This frequency is not significantly higher than expected for a pathogenic variant in PMM2 causing Congenital Disorder of Glycosylation Type 1a (4.4e-05 vs 0.0056), allowing no conclusion about variant significance. c.710C>T has been reported in the literature in multiple individuals affected with Congenital Disorder of Glycosylation Type 1a (example, Matthijs_1997, Briones_2001, Tayebi_2002, Bortot_2013, Vega_2011). These data indicate that the variant is very likely to be associated with disease. At least two publications report experimental evidence evaluating an impact on protein function. The most pronounced variant effect results in 10%-<30% of normal activity due to a destabilizing outcome on folding (example Vega_2011 and Yuste-Checa_2015). Six clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic (n=5)/likely pathogenic (n=1). Based on the evidence outlined above, the variant was classified as pathogenic. -
This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 237 of the PMM2 protein (p.Thr237Met). This variant is present in population databases (rs80338708, gnomAD 0.01%). This missense change has been observed in individual(s) with congenital disorder of glycosylation type 1 (PMID: 11589167, 11891694, 21541725, 23430838, 23988505). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 21145). 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 PMM2 protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects PMM2 function (PMID: 21541725, 26014514). For these reasons, this variant has been classified as Pathogenic. -
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The variant c.710C>T has been reported in a homozygous state in similarly affected individuals with congenital disorder of glycosylation, type Ia earlier (Matthijs et al., 1997). This variant was also reported in the ClinVar database as a likely pathogenic/pathogenic variant in 17 independent submissions (ClinVar ID: 21145). In silico prediction tools (MutationTaster, CADD phred, and REVEL) are consistent in predicting the variant to be damaging to PMM2 protein function. -
not provided Pathogenic:5
PMM2: PM3:Very Strong, PM2, PM5, PP4:Moderate, PS3:Supporting -
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Published functional studies demonstrate a reduced residual activity in T237M when compared with wild type, and T237M was identified as destabilizing variant (Vega et al., 2011; Yuste-Checa et al., 2015); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 10801058, 28685491, 11589167, 21541725, 9140401, 23988505, 11891694, 26014514, 15844218, 11156536, 11058895, 27774737, 19235233, 28425223, 12705494, 31736265, 33413482) -
PS3, PS4, PM2, PM3, PM5, PP3, PP4, PP5 -
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Inborn genetic diseases Pathogenic:1
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PMM2-related disorder Pathogenic:1
The PMM2 c.710C>T variant is predicted to result in the amino acid substitution p.Thr237Met. This variant has been documented as causative for autosomal recessive congenital disorder of glycosylation type Ia when present with a second causative variant (Matthijs et al. 1997. PubMed ID: 9140401; Tayebi et al. 2002. PubMed ID: 11891694; Bortot et al. 2013. PubMed ID: 23988505). Functional studies have shown that the p.Thr237Met substitution causes a partial decrease in protein abundance and residual enzymatic activity, and the authors suggest a mild classification for this variant (Vega et al. 2011. PubMed ID: 21541725; Yuste-Checa et al. 2015. PubMed ID: 26014514). This variant is reported in 0.013% of alleles in individuals of South Asian descent in gnomAD. Given the evidence, we interpret c.710C>T (p.Thr237Met) as pathogenic. -
Intellectual disability Pathogenic:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at