chr14-75042464-C-A

Position:

• chr14-75042464-C-A

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4 BS2

The NM_001040108.2(MLH3):​c.3294G>T​(p.Arg1098Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000171 in 1,461,018 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000017 (0 hom.)
• Consequence: MLH3 NM_001040108.2 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.621

Genes affected

MLH3 (HGNC:7128): (mutL homolog 3) This gene is a member of the MutL-homolog (MLH) family of DNA mismatch repair (MMR) genes. MLH genes are implicated in maintaining genomic integrity during DNA replication and after meiotic recombination. The protein encoded by this gene functions as a heterodimer with other family members. Somatic mutations in this gene frequently occur in tumors exhibiting microsatellite instability, and germline mutations have been linked to hereditary nonpolyposis colorectal cancer type 7 (HNPCC7). Several alternatively spliced transcript variants have been identified, but the full-length nature of only two transcript variants has been determined. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -5 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.37756568).
• BS2: High AC in GnomAdExome4 at 25 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MLH3	NM_001040108.2	c.3294G>T	p.Arg1098Ser	missense_variant	3/13	ENST00000355774.7	NP_001035197.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MLH3	ENST00000355774.7	c.3294G>T	p.Arg1098Ser	missense_variant	3/13	5	NM_001040108.2	ENSP00000348020	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251482 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135914

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000171 AC: 25 AN: 1461018 Hom.: 0 Cov.: 30 AF XY: 0.0000151 AC XY: 11 AN XY: 726914

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000207

Gnomad4 OTH exome AF: 0.0000331

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 21, 2021

The p.R1098S variant (also known as c.3294G>T), located in coding exon 2 of the MLH3 gene, results from a G to T substitution at nucleotide position 3294. The arginine at codon 1098 is replaced by serine, 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. -

Colorectal cancer, hereditary nonpolyposis, type 7 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 21, 2021

In summary, this variant is a novel missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a MLH3-related disease. This sequence change replaces arginine with serine at codon 1098 of the MLH3 protein (p.Arg1098Ser). The arginine residue is moderately conserved and there is a moderate physicochemical difference between arginine and serine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.41
BayesDel_addAF	Uncertain	0.075	D
BayesDel_noAF	Benign	-0.13
CADD	Benign	20
DANN	Uncertain	1.0
DEOGEN2	Benign	0.13	T;.;T
Eigen	Benign	0.17
Eigen_PC	Benign	0.15
FATHMM_MKL	Benign	0.75	D
LIST_S2	Uncertain	0.87	D;D;.
M_CAP	Uncertain	0.14	D
MetaRNN	Benign	0.38	T;T;T
MetaSVM	Uncertain	0.41	D
MutationAssessor	Uncertain	2.5	M;M;M
MutationTaster	Benign	0.61	D;D;D;D;D;N
PrimateAI	Benign	0.35	T
PROVEAN	Benign	-2.0	N;.;N
REVEL	Uncertain	0.38
Sift	Uncertain	0.013	D;.;D
Sift4G	Uncertain	0.0050	D;D;D
Polyphen		0.73	P;D;P
Vest4		0.34
MutPred		0.41		Gain of catalytic residue at R1103 (P = 0.0146);Gain of catalytic residue at R1103 (P = 0.0146);Gain of catalytic residue at R1103 (P = 0.0146);
MVP		0.88
MPC		0.34
ClinPred		0.90	D
GERP RS		1.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.17
gMVP		0.71

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: rs1060503068; hg19: chr14-75509167;