chr3-149185366-G-A
Variant summary
Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4_Moderate
The NM_000096.4(CP):c.2158C>T(p.Arg720Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000436 in 1,613,932 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).
Frequency
Consequence
NM_000096.4 missense
Scores
Clinical Significance
Conservation
Publications
- aceruloplasminemiaInheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet, Labcorp Genetics (formerly Invitae), Ambry Genetics
- disorder of iron metabolism and transportInheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
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ACMG classification
Our verdict: Likely_benign. The variant received -2 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000224 AC: 34AN: 152070Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.000215 AC: 54AN: 251422 AF XY: 0.000243 show subpopulations
GnomAD4 exome AF: 0.000458 AC: 670AN: 1461862Hom.: 0 Cov.: 32 AF XY: 0.000407 AC XY: 296AN XY: 727224 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.000224 AC: 34AN: 152070Hom.: 0 Cov.: 32 AF XY: 0.000162 AC XY: 12AN XY: 74274 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Deficiency of ferroxidase Pathogenic:1Uncertain:4
This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 720 of the CP protein (p.Arg720Trp). This variant is present in population databases (rs145784949, gnomAD 0.04%). This missense change has been observed in individual(s) with clinical features of aceruloplasminemia (PMID: 15654567, 29482220). ClinVar contains an entry for this variant (Variation ID: 42123). 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 CP protein function. Experimental studies have shown that this missense change affects CP function (PMID: 19095659, 20430895, 20655381, 22281056). 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. -
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Based on the classification scheme VCGS_Germline_v1.3.5, this variant is classified as VUS-3B. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with aceruloplasminemia (MIM#604290). Dominant-negative has also been suggested as a mechanism of disease. (I) 0106 - This gene is associated with autosomal recessive disease. (I) 0200 - Variant is predicted to result in a missense amino acid change from arginine to tryptophan. (I) 0251 - This variant is heterozygous. (I) 0304 - Variant is present in gnomAD (v4) <0.01 for a recessive condition (704 heterozygotes, 0 homozygotes). (SP) 0502 - Missense variant with conflicting in silico predictions and uninformative conservation. (I) 0604 - Variant is not located in an established domain, motif, hotspot or informative constraint region. (I) 0705 - No comparable missense variants have previous evidence for pathogenicity. (I) 0808 - Previous reports of pathogenicity for this variant are conflicting. This variant has been classified as a VUS by nine clinical testing laboratories (ClinVar). It has been reported in a compound heterozygous state in an individual with aceruloplasminemia (PMID: 29482220). Additionally, this variant has been reported in a heterozygous state in affected individual in whom it was unclear whether a second variant was not detected (PMID: 15654567), and in an individual with an alternative genetic diagnosis (PMID: 32753443). Individuals heterozygous for this variant can have reduced serum copper and caeruloplasmin levels. (I) 0905 - No published segregation evidence has been identified for this variant. (I) 1002 - This variant has moderate functional evidence supporting abnormal protein function. Functional studies indicated that this variant results in impaired oxidase activity (PMIDs: 19095659, 20430895, 20655381). (SP) 1206 - This variant has been shown to be paternally inherited (by trio analysis). (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -
not provided Uncertain:5
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not specified Uncertain:1
Variant summary: CP c.2158C>T (p.Arg720Trp) results in a non-conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00021 in 251422 control chromosomes. The observed variant frequency is approximately equal to the estimated maximal expected allele frequency for a pathogenic variant in CP causing Neurodegeneration With Brain Iron Accumulation phenotype (0.00019). c.2158C>T has been reported in the literature in heterozygous individuals (without a known pathogenic variant detected in trans) affected with aceruloplasminemia, but it was also reported in their unaffected heterozygous parents (Kuhn_2005, Hines_2018). These reports do not provide unequivocal conclusions about association of the variant with Neurodegeneration With Brain Iron Accumulation. The variant has been reported to confer a dominant negative effect on wild type CP (di Patti_2009). Experimental evidence from cell culture models demonstrated that it correctly reaches the plasma membrane, but fails to stabilize ferroportin on cell surface due to inherently impaired oxidase activity. It was further shown to induce fragmentation/dispersal of the Golgi apparatus and impair the proper functioning of ATP7B, which becomes unable to discharge copper into the target ferroxidase; these effects being accompanied by the massive production of reactive oxygen species in the cell (di Patti_2009, Kono_2010, Maio_2010, Persichini_2012). The following publications have been ascertained in the context of this evaluation (PMID: 29482220, 20655381, 15654567, 20430895, 22281056, 19095659). ClinVar contains an entry for this variant (Variation ID:42123). Based on the evidence outlined above, the variant was classified as uncertain significance. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at