The ClinGen Evidence Repository is an FDA-recognized human genetic variant database containing expert-curated assertions regarding variants' pathogenicity and supporting evidence summaries.
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- See Evidence submitted by expert panel for details.
Variant: NM_004958.4(MTOR):c.4379T>C (p.Leu1460Pro)
CA16602588
376130 (ClinVar)
Gene: MTOR
Condition: overgrowth syndrome and/or cerebral malformations due to abnormalities in MTOR pathway genes
Inheritance Mode: Autosomal dominant inheritance (mosaic)
UUID: 4aec1681-4a5e-413f-a6e7-6eb9120dcec6
HGVS expressions
NM_004958.4:c.4379T>C
NM_004958.4(MTOR):c.4379T>C (p.Leu1460Pro)
NC_000001.11:g.11157242A>G
CM000663.2:g.11157242A>G
NC_000001.10:g.11217299A>G
CM000663.1:g.11217299A>G
NC_000001.9:g.11139886A>G
NG_033239.1:g.110310T>C
ENST00000361445.9:c.4379T>C
ENST00000361445.8:c.4379T>C
NM_004958.3:c.4379T>C
NM_001386500.1:c.4379T>C
NM_001386501.1:c.3131T>C
Pathogenic
Met criteria codes 6
PP2
PS2_Moderate
PM2_Supporting
PS3_Supporting
PM1_Supporting
PS4
Not Met criteria codes 20
PP1
PP4
PP3
PM6
PM4
PM3
PM5
PVS1
BA1
BS2
BS4
BS3
BS1
BP7
BP5
BP3
BP2
BP1
BP4
PS1
Evidence Links 6
Expert Panel
Evidence submitted by expert panel
Brain Malformations VCEP
The c.4379T>C (NM_004958.4) variant in MTOR is a missense variant predicted to cause substitution of (p.Leu1460Pro). This variant is absent from gnomAD v2.1.1 (PM2_Supporting). MTOR, in which the variant was identified, is defined by the ClinGen Brain Malformations Expert Panel as a gene that has a low rate of benign missense variation and where pathogenic missense variants are a common mechanism of disease (PP2). This variant resides within the kinase domain of MTOR that is defined as a critical functional domain by the ClinGen BMEP (PMIDs: 23322780, 27482884, 21210909) (PM1_Supporting). This variant has been shown to significantly increase phosphorylation levels in experiments with case and controls cells of similar isogenic backgrounds indicating that this variant impacts protein function (PMID: 27159400) (PS3_Supporting). The prevalence of the variant in affected individuals is significantly increased compared with the prevalence in controls (PS4; PMIDs: 26018084, 29281825, 27159400, 26831717; 3 individuals with neuropathology confirmatory of a malformation of cortical development, 1 individual with neuroimaging appearance consistent with a malformation of cortical development (without neuropathology), 4 tumor samples in the literature and COSMIC ). Testing of unaffected and affected tissue show variable allelic fractions consistent with a post-zygotic event (PS2_Moderate; PMID: 29281825, 26018084, 27159400). In summary, this variant meets the criteria to be classified as Pathogenic for mosaic autosomal dominant overgrowth with or without cerebral malformations due to abnormalities in MTOR-pathway genes based on the ACMG/AMP criteria applied, as specified by the ClinGen Brain Malformations Expert Panel: PM2_P, PP2, PM1_P, PS3_P, PS4, PS2_M; 10 points (VCEP specifications version 1; Approved: 1/31/2021)
Met criteria codes
PP2
Z score is 7.89
PS2_Moderate
Somatic in brain and blood
Thirteen individuals with various types of FCD were screened for somatic MTOR variants. Two indivisuals with FCD IIB were identified with this varinat. The variants were identified in both blood and brain in various allelic fractions, 1.6% brain/.06% blood 4.9% brain/ .05% blood. In both cases the variant was detectable in blood but at a lower alleic fraction
PubMed:26018084
Identified in an individual with an FCD IIA at an allelic ratio of 0.06 in brain and 0.0 in blood
PubMed:27159400
Patient FCD-6 carries MTOR variant p.L1460P in 4.6%–5.2% of cells based on next-generation sequencing (NGS), with 7.1% ± 1.8% of NeuN+ cells and 0.53% ± 0.53% of NeuN cells carrying the mutation (p < 0.001, two-tailed Fisher’s exact test)
PubMed:29281825
PM2_Supporting
Absent from controls in Gnomad and Exac
PS3_Supporting
This variant was expressed in HEK293T cells and phosphorylation of the mTORC1/2 substrates S6K1, 4EBP1, or Akt1 examined. This variant showed significant over phosphorylation across these assays.
PubMed:24631838
Various functional assays were utilized to determine the effect of these variants in transfected HEK293 cells. In vitro kinase activities showed this variant results in consititutive activation.
PubMed:17360675
PM1_Supporting
Cancer-associated MTOR variants were found to cluster in certain areas of the protein. This variant was located in a region the authors called the F1 cluster. Coimmunoprecipitation assays revealed the F1 cluster region may be the binding area for DEPTOR,a negative regulator of MTOR. This variant's presence in this cluser is therefore believed to cause decrease binding affinity to DEPTOR and result in increase activity.
PubMed:27482884
PS4
2 individuals is moderate evidence, 4 tumor samples in COSMIC
Thirteen individuals with various types of FCD were screened for somatic MTOR variants, using a combination of WES and droplet PCR. Two indivisuals with FCD IIB were identified with this varinat with allelic fractions in the somatic range.
PubMed:26018084
Neuroimaging appearance consistent with a malformation of cortical development (without neuropathology)
PubMed:29281825
1 individual with an FCD IIA
PubMed:27159400
Not Met criteria codes
PP1
No code specific comments provided, please refer to the summary above or general recommendations provided in the guideline
PP4
No code specific comments provided, please refer to the summary above or general recommendations provided in the guideline
PP3
Conflicting lines of evidence
PM6
Thirteen individuals with various types of FCD were screened for somatic MTOR variants. Two indivisuals with FCD IIB were identified with this varinat. The variants were identified in both blood and brain in various allelic fractions, 1.6% brain/.06% blood 4.9% brain/ .05% blood. In both cases the variant was detectable in blood but at a lower alleic fraction
PubMed:26018084
Identified in an individual with an FCD IIA at an allelic ratio of 0.06 in brain and 0.0 in blood
PubMed:27159400
Patient FCD-6 carries MTOR variant p.L1460P in 4.6%–5.2% of cells based on next-generation sequencing (NGS), with 7.1% ± 1.8% of NeuN+ cells and 0.53% ± 0.53% of NeuN cells carrying the mutation (p < 0.001, two-tailed Fisher’s exact test)
PubMed:29281825
PM4
No code specific comments provided, please refer to the summary above or general recommendations provided in the guideline
PM3
No code specific comments provided, please refer to the summary above or general recommendations provided in the guideline
PM5
No code specific comments provided, please refer to the summary above or general recommendations provided in the guideline
PVS1
No code specific comments provided, please refer to the summary above or general recommendations provided in the guideline
BA1
Absent from controls in Gnomad and Exac
BS2
No code specific comments provided, please refer to the summary above or general recommendations provided in the guideline
BS4
No code specific comments provided, please refer to the summary above or general recommendations provided in the guideline
BS3
No code specific comments provided, please refer to the summary above or general recommendations provided in the guideline
BS1
Absent from controls in Gnomad and Exac
BP7
No code specific comments provided, please refer to the summary above or general recommendations provided in the guideline
BP5
No code specific comments provided, please refer to the summary above or general recommendations provided in the guideline
BP3
No code specific comments provided, please refer to the summary above or general recommendations provided in the guideline
BP2
No code specific comments provided, please refer to the summary above or general recommendations provided in the guideline
BP1
Z score is 7.89
BP4
Conflicting lines of evidence
PS1
No code specific comments provided, please refer to the summary above or general recommendations provided in the guideline
Approved on: 2022-02-11
Published on: 2022-02-11
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