4-83462482-G-T

Variant names:

• chr4-83462482-G-T
• rs1325575122
• NM_139076.3:c.1217C>A

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1 PM2 PP3

The NM_139076.3(ABRAXAS1):​c.1217C>A​(p.Ser406Tyr) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: ABRAXAS1 NM_139076.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 6.17

Genes affected

ABRAXAS1 (HGNC:25829): (abraxas 1, BRCA1 A complex subunit) This gene encodes a protein that binds to the C-terminal repeats of breast cancer 1 (BRCA1) through a phospho-SXXF motif. The encoded protein recruits ubiquitin interaction motif containing 1 protein to BRCA1 protein and is required for DNA damage resistance, DNA repair, and cell cycle checkpoint control. Pseudogenes of this gene are found on chromosomes 3 and 8. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Sep 2016]

MRPS18C (HGNC:16633): (mitochondrial ribosomal protein S18C) Mammalian mitochondrial ribosomal proteins are encoded by nuclear genes and help in protein synthesis within the mitochondrion. Mitochondrial ribosomes (mitoribosomes) consist of a small 28S subunit and a large 39S subunit. They have an estimated 75% protein to rRNA composition compared to prokaryotic ribosomes, where this ratio is reversed. Another difference between mammalian mitoribosomes and prokaryotic ribosomes is that the latter contain a 5S rRNA. Among different species, the proteins comprising the mitoribosome differ greatly in sequence, and sometimes in biochemical properties, which prevents easy recognition by sequence homology. This gene encodes a 28S subunit protein that belongs to the ribosomal protein S18P family. The encoded protein is one of three that has significant sequence similarity to bacterial S18 proteins. The primary sequences of the three human mitochondrial S18 proteins are no more closely related to each other than they are to the prokaryotic S18 proteins. Pseudogenes corresponding to this gene are found on chromosomes 8p, 12p, 15q, and 22q. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM1: In a mutagenesis_site Abolishes phosphorylation of the pSXXF motif and the interaction with BRCA1 but does not affect the interaction with UIMC1/RAP80. Strongly decreases recruitment of BRCA1 to sites of DNA damage. No effect on homodimerization. (size 0) in uniprot entity ABRX1_HUMAN
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.768

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ABRAXAS1	NM_139076.3	c.1217C>A	p.Ser406Tyr	missense_variant	Exon 9 of 9	ENST00000321945.12	NP_620775.2
MRPS18C	NM_016067.4	c.*1285G>T		downstream_gene_variant		ENST00000295491.9	NP_057151.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ABRAXAS1	ENST00000321945.12	c.1217C>A	p.Ser406Tyr	missense_variant	Exon 9 of 9	1	NM_139076.3	ENSP00000369857.3
MRPS18C	ENST00000295491.9	c.*1285G>T		downstream_gene_variant		1	NM_016067.4	ENSP00000295491.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 33

Alfa AF: 0.0000329 Hom.: 0

Bravo AF: 0.0000151

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Jun 10, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.S406Y variant (also known as c.1217C>A), located in coding exon 9 of the FAM175A gene, results from a C to A substitution at nucleotide position 1217. The serine at codon 406 is replaced by tyrosine, an amino acid with dissimilar properties. This amino acid position is conserved. 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. -

not provided Uncertain:1

Feb 11, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. 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 (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). ClinVar contains an entry for this variant (Variation ID: 953515). This variant has not been reported in the literature in individuals affected with ABRAXAS1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces serine, which is neutral and polar, with tyrosine, which is neutral and polar, at codon 406 of the ABRAXAS1 protein (p.Ser406Tyr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.40
BayesDel_addAF	Uncertain	0.15	D
BayesDel_noAF	Uncertain	-0.020
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.10	T;.
Eigen	Pathogenic	0.75
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Benign	0.81	T;T
M_CAP	Benign	0.033	D
MetaRNN	Pathogenic	0.77	D;D
MetaSVM	Uncertain	-0.25	T
PrimateAI	Benign	0.47	T
PROVEAN	Uncertain	-3.2	D;D
REVEL	Benign	0.26
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;.
Vest4		0.72
MVP		0.72
MPC		0.58
ClinPred		0.99	D
GERP RS		5.2
Varity_R		0.59
gMVP		0.52

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1325575122; hg19: chr4-84383635;