rs533273863
Variant summary
Our verdict is Likely benign. The variant received -1 ACMG points: 0P and 1B. BP4
The NM_174936.4(PCSK9):c.520C>T(p.Pro174Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000125 in 1,613,846 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P174L) has been classified as Uncertain significance.
Frequency
Consequence
NM_174936.4 missense
Scores
Clinical Significance
Conservation
Publications
- hypercholesterolemia, autosomal dominant, 3Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: ClinGen, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Ambry Genetics
- homozygous familial hypercholesterolemiaInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Likely_benign. The variant received -1 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000789 AC: 12AN: 152044Hom.: 0 Cov.: 31 show subpopulations
GnomAD2 exomes AF: 0.0000718 AC: 18AN: 250796 AF XY: 0.0000811 show subpopulations
GnomAD4 exome AF: 0.000130 AC: 190AN: 1461684Hom.: 0 Cov.: 32 AF XY: 0.000132 AC XY: 96AN XY: 727138 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000789 AC: 12AN: 152162Hom.: 0 Cov.: 31 AF XY: 0.000108 AC XY: 8AN XY: 74382 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Hypercholesterolemia, autosomal dominant, 3 Uncertain:3
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This sequence change replaces proline, which is neutral and non-polar, with serine, which is neutral and polar, at codon 174 of the PCSK9 protein (p.Pro174Ser). This variant is present in population databases (rs533273863, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with PCSK9-related conditions. ClinVar contains an entry for this variant (Variation ID: 496561). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The serine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. Experimental studies have shown that this missense change affects PCSK9 function (PMID: 31386798). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
This missense variant replaces proline with serine at codon 174 of the PCSK9 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). A functional study has shown the mutant protein to exhibit loss of function phenotype both extracellularly and intracellularly, which is likely due to a weaker binding to the LDLR protein (PMID: 31386798). This variant has been observed in individuals with lower than expected cholesterol (PMID: 22417841, 23997648), as well as in an individual affected with hypercholesterolemia (PMID: 33418990). This variant has also been observed in healthy individuals over age 70 without coronary heart disease, where the mean LDL level of carriers (127.6 mg/dl) was slightly higher than that of non-carriers (119.9 mg/dl) (PMID: 34341098). This variant has been identified in 20/282112 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
not provided Uncertain:2
Identified in a family with FH who also harbored a homozygous variant in the LDLR gene; most family members who were homozygous for both variants showed an attenuated phenotype, suggesting that this PCSK9 variant may reduce the severity of FH by acting as a loss-of-function variant (PMID: 22417841); Functional studies have shown a loss of function effect, which is inconsistent with the known gain of function mechanism of disease (PMID: 31386798); In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 30218657, 25985138, 28521186, 33418990, 23997648, 34341098, 25911074, 22417841, 30415195, 31386798) -
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not specified Uncertain:1
Variant summary: PCSK9 c.520C>T (p.Pro174Ser) results in a non-conservative amino acid change in the encoded protein sequence. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change. The variant allele was found at a frequency of 7.2e-05 in 250996 control chromosomes. The observed variant frequency is approximately 1.91 fold of the estimated maximal expected allele frequency for a pathogenic variant in PCSK9 causing Familial Hypercholesterolemia phenotype (3.8e-05). c.520C>T has been observed in individual(s) affected with Familial Hypercholesterolemia (2012). These report(s) do not provide unequivocal conclusions about association of the variant with Familial Hypercholesterolemia. At least one publication reports experimental evidence evaluating an impact on protein function, however, does not allow convincing conclusions about the variant effect (Mikaeeli_2020). The following publications have been ascertained in the context of this evaluation (PMID: 22417841, 25985138, 31386798). ClinVar contains an entry for this variant (Variation ID: 496561). Based on the evidence outlined above, the variant was classified as uncertain significance. -
Cardiovascular phenotype Uncertain:1
The p.P174S variant (also known as c.520C>T), located in coding exon 3 of the PCSK9 gene, results from a C to T substitution at nucleotide position 520. The proline at codon 174 is replaced by serine, an amino acid with some similar properties. This variant was previously observed in conjunction with a mutation in the LDLR gene in a family with familial hypercholesterolemia (FH). The proband, who was homozygous for both the LDLR mutation and this variant, presented with what was considered an attenuated homozygous FH phenotype. In addition, five relatives with both alterations had lower than expected LDL levels for heterozygous FH. However, one relative with both alterations had LDL levels consistent with heterozygous FH (Slimani A et al. Atherosclerosis. 2012;222(1):158-66). This variant also co-occurred with an APOB mutation in an individual from a FH cohort and co-occurred with two mutations in ABCG8 in a proband with hypercholesterolemia and sitosterolemia without xanthomas whose mother had this variant and one ABCG8 mutation and normal cholesterol levels (Buonuomo PS et al. Atherosclerosis. 2017 07;262:71-77; Meshkov A et al. Genes (Basel). 2021 01;12(1)). One in vitro functional study has indicated that this variant may result in loss of function and weaker binding to LDLR protein (Mikaeeli S et al. FEBS J. 2020 02;287(3):515-528). This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Familial hypercholesterolemia Uncertain:1
This missense variant replaces proline with serine at codon 174 of the PCSK9 protein. Computational prediction tools indicate that this variant has a neutral impact on protein structure and function. A functional study has shown the mutant protein to exhibit a loss of function phenotype both extracellularly and intracellularly, which is likely due to a weaker binding to the LDLR protein (PMID: 31386798). This variant has been observed in individuals with lower than expected cholesterol (PMID: 22417841, 23997648), as well as in one individual affected with hypercholesterolemia (PMID: 33418990). This variant has also been observed in healthy individuals over age 70 without coronary heart disease, where the mean LDL level of carriers (127.6 mg/dl) was slightly higher than that of non-carriers (119.9 mg/dl) (PMID: 34341098). This variant has been identified in 20/282112 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at