5-80654728-A-C

Variant names:

• chr5-80654728-A-C
• NM_002439.5:c.1A>C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_002439.5(MSH3):​c.1A>C​(p.Met1?) variant causes a initiator codon change involving the alteration of a non-conserved nucleotide. 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: 32)
• Consequence: MSH3 NM_002439.5 initiator_codon
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.22

Genes affected

MSH3 (HGNC:7326): (mutS homolog 3) The protein encoded by this gene forms a heterodimer with MSH2 to form MutS beta, part of the post-replicative DNA mismatch repair system. MutS beta initiates mismatch repair by binding to a mismatch and then forming a complex with MutL alpha heterodimer. This gene contains a polymorphic 9 bp tandem repeat sequence in the first exon. The repeat is present 6 times in the reference genome sequence and 3-7 repeats have been reported. Defects in this gene are a cause of susceptibility to endometrial cancer. [provided by RefSeq, Mar 2011]

DHFR (HGNC:2861): (dihydrofolate reductase) Dihydrofolate reductase converts dihydrofolate into tetrahydrofolate, a methyl group shuttle required for the de novo synthesis of purines, thymidylic acid, and certain amino acids. While the functional dihydrofolate reductase gene has been mapped to chromosome 5, multiple intronless processed pseudogenes or dihydrofolate reductase-like genes have been identified on separate chromosomes. Dihydrofolate reductase deficiency has been linked to megaloblastic anemia. Several transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Mar 2014]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PVS1: Start lost variant, next in-frame start position is after 1 pathogenic variants. Next in-frame start position is after 115 codons. Genomic position: 80656516. Lost 0.100 part of the original CDS.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MSH3	NM_002439.5	c.1A>C	p.Met1?	initiator_codon_variant	Exon 1 of 24	ENST00000265081.7	NP_002430.3
DHFR	NM_000791.4	c.-239T>G		5_prime_UTR_variant	Exon 1 of 6	ENST00000439211.7	NP_000782.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MSH3	ENST00000265081.7	c.1A>C	p.Met1?	initiator_codon_variant	Exon 1 of 24	1	NM_002439.5	ENSP00000265081.6
MSH3	ENST00000667069.1	c.1A>C	p.Met1?	initiator_codon_variant	Exon 1 of 22			ENSP00000499502.1
DHFR	ENST00000439211.7	c.-239T>G		5_prime_UTR_variant	Exon 1 of 6	1	NM_000791.4	ENSP00000396308.2
MSH3	ENST00000670357.1	n.1A>C		non_coding_transcript_exon_variant	Exon 1 of 25			ENSP00000499791.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Jul 07, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects the initiator methionine of the MSH3 mRNA. The next in-frame methionine is located at codon 115. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with MSH3-related conditions. Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.39	D
BayesDel_noAF	Pathogenic	0.33
CADD	Benign	22
DANN	Benign	0.95
DEOGEN2	Benign	0.19	T
Eigen	Benign	0.087
Eigen_PC	Benign	0.058
FATHMM_MKL	Benign	0.61	D
LIST_S2	Uncertain	0.90	D
M_CAP	Pathogenic	1.0	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Uncertain	0.22	D
PROVEAN	Benign	-0.36	N
REVEL	Uncertain	0.63
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		0.70	P
Vest4		0.82
MutPred		0.99		Loss of methylation at K5 (P = 0.0912);
MVP		0.89
ClinPred		1.0	D
GERP RS		4.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.97
gMVP		0.49

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr5-79950547;