NM_000312.4:c.658C>T
Variant summary
Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM2PM5PP3_ModeratePP5_Very_Strong
The NM_000312.4(PROC):c.658C>T(p.Arg220Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000744 in 1,613,846 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 Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R220Q) has been classified as Likely pathogenic.
Frequency
Consequence
NM_000312.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 14 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152112Hom.: 0 Cov.: 32
GnomAD4 exome AF: 0.00000753 AC: 11AN: 1461734Hom.: 0 Cov.: 31 AF XY: 0.00000688 AC XY: 5AN XY: 727170
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152112Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1AN XY: 74290
ClinVar
Submissions by phenotype
Thrombophilia due to protein C deficiency, autosomal dominant Pathogenic:3
We found a four-generation Chinese pedigree with hereditary thrombophilia, comprising seven affected individuals presenting recurrent thrombotic events involving both venous and arterial systems. Clinical manifestations included pulmonary embolism, chronic pulmonary hypertension, lower extremity deep vein thrombosis, and arterial thrombosis. Genetic analysis via next-generation sequencing (NGS) followed by Sanger validation identified a heterozygous missense mutation in the PROC gene (NM_000312.4: c.658C>T [p.Arg220Trp]) segregating with the phenotype in the proband and all symptomatic family members. Western blot and ELISA demonstrated increased intracellular PC expression and elevated secretion levels in culture supernatants compared to wild-type (WT) controls. In contrast, chromogenic assays assessing plasma anticoagulant activity showed significantly reduced activated protein C (APC) activity in mutation carriers, consistent with impaired functional capacity despite heightened protein abundance. These results indicate that the mutation will cause high secretion-low expression of APC. -
This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 220 of the PROC protein (p.Arg220Trp). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with protein C deficiency (PMID: 1511989, 1868249, 25393254, 31254973). It has also been observed to segregate with disease in related individuals. This variant is also known as Arg178Trp. ClinVar contains an entry for this variant (Variation ID: 668). 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 not expected to disrupt PROC protein function. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. This variant disrupts the p.Arg220 amino acid residue in PROC. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 1301954, 1301959, 1511989, 7605880, 8499565, 18954896, 31254973). 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. -
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PROC-related disorder Pathogenic:1
The PROC c.658C>T variant is predicted to result in the amino acid substitution p.Arg220Trp. This variant, described as R178W using legacy nomenclature, segregated with autosomal dominant protein C deficiency in two unrelated families (Reitsma et al. 1991. PubMed ID: 1868249; Grundy et al. 1992. PubMed ID: 1511989), although some individuals were symptomatic while others were asymptomatic. This variant has also been observed in the compound heterozygous state in an individual with severe venous thromboembolic disease (Wu et al. 2014. PubMed ID: 25393254) and has been reported along with a second variant in this gene in one individual with protein C deficiency (Tang. et al. 2022. PubMed ID: 35026611). Alternative missense changes at the same amino acid position (i.e. p.Arg220Gly and p.Arg220Gln) have been reported in patients with protein C deficiency (David et al. 2011. PubMed ID: 21621249; Reitsma et al. 1991. PubMed ID: 1868249; Grundy et al. 1992. PubMed ID: 1511989). This variant has not been reported in a large population database, indicating this variant is rare. This variant is interpreted as pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at