NM_005957.5:c.968T>C
Variant summary
Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PM1PM2PP3_StrongPP5_Very_Strong
The NM_005957.5(MTHFR):c.968T>C(p.Leu323Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000744 in 1,613,592 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. L323L) has been classified as Likely benign.
Frequency
Consequence
NM_005957.5 missense
Scores
Clinical Significance
Conservation
Publications
- homocystinuria due to methylene tetrahydrofolate reductase deficiencyInheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), G2P, ClinGen, Orphanet
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ACMG classification
Our verdict: Pathogenic. The variant received 16 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152192Hom.: 0 Cov.: 33 show subpopulations
GnomAD2 exomes AF: 0.0000120 AC: 3AN: 250910 AF XY: 0.0000147 show subpopulations
GnomAD4 exome AF: 0.00000753 AC: 11AN: 1461400Hom.: 0 Cov.: 32 AF XY: 0.00000413 AC XY: 3AN XY: 727018 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152192Hom.: 0 Cov.: 33 AF XY: 0.0000134 AC XY: 1AN XY: 74356 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Homocystinuria due to methylene tetrahydrofolate reductase deficiency Pathogenic:3
This sequence change replaces leucine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 323 of the MTHFR protein (p.Leu323Pro). This variant is present in population databases (rs121434297, gnomAD 0.003%). This missense change has been observed in individual(s) with severe methylenetetrahydrofolate reductase deficiency (PMID: 8940272, 25162892, 34214447). This variant is also known as T980C. ClinVar contains an entry for this variant (Variation ID: 3529). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on MTHFR protein function. Experimental studies have shown that this missense change affects MTHFR function (PMID: 10551815). For these reasons, this variant has been classified as Pathogenic. -
Variant summary: MTHFR c.968T>C (p.Leu323Pro) 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 1.2e-05 in 250910 control chromosomes. c.968T>C has been reported in the literature in at-least two individuals affected with Homocystinuria Due To Methylene Tetrahydrofolate Reductase Deficiency (Sahai_2014, Goyette_1996). These data indicate that the variant may be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect results in <10% of normal activity and incapacity to complement the auxotrophic phenotype of the cells deficient of MTHFR (Shan_1999, Weile_2021). The following publications have been ascertained in the context of this evaluation (PMID: 8940272, 25162892, 10551815, 34214447). ClinVar contains an entry for this variant (Variation ID: 3529). Based on the evidence outlined above, the variant was classified as likely pathogenic. -
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Schizophrenia;C1856061:Homocystinuria due to methylene tetrahydrofolate reductase deficiency;C1866558:Neural tube defects, folate-sensitive;C3160733:Thrombophilia due to thrombin defect Pathogenic:1
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Neural tube defects, folate-sensitive Pathogenic:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at