rs1064795526

Positions:

• chr3-36993532-C-G
• chr3-36993532-C-T

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_000249.4(MLH1):​c.-16C>G variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,434 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: 33)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: MLH1 NM_000249.4 5_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.0770

Genes affected

MLH1 (HGNC:7127): (mutL homolog 1) The protein encoded by this gene can heterodimerize with mismatch repair endonuclease PMS2 to form MutL alpha, part of the DNA mismatch repair system. When MutL alpha is bound by MutS beta and some accessory proteins, the PMS2 subunit of MutL alpha introduces a single-strand break near DNA mismatches, providing an entry point for exonuclease degradation. The encoded protein is also involved in DNA damage signaling and can heterodimerize with DNA mismatch repair protein MLH3 to form MutL gamma, which is involved in meiosis. This gene was identified as a locus frequently mutated in hereditary nonpolyposis colon cancer (HNPCC). [provided by RefSeq, Aug 2017]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.76).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MLH1	NM_000249.4	c.-16C>G		5_prime_UTR_variant	1/19	ENST00000231790.8	NP_000240.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8	c.-16C>G		5_prime_UTR_variant	1/19	1	NM_000249.4	ENSP00000231790	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461434 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727090

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: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Aug 18, 2016

This variant is denoted MLH1 c.-16C>G and describes a nucleotide substitution 16 base pairs upstream of the ATG translational start site in the 5' untranslated region (UTR). The surrounding sequence, with the base that is substituted in braces, is TTGG[C/G]TCTT. This variant has not, to our knowledge, been published in the literature as pathogenic or benign. MLH1 c.-16C>G was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, suggesting it is not a common benign variant in these populations. Of note, constitutional epigenetic silencing of MLH1 has been suggested as an alternate mechanism responsible for Lynch syndrome and variants located within the 5' UTR have been shown to result in allele specific promoter methylation and subsequent transcriptional silencing (Hitchins 2009, Ward 2013). Based on currently available information, it is unclear whether MLH1 c.-16C>G is pathogenic or benign. We consider it to be a variant of uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.76
CADD	Benign	6.0
DANN	Benign	0.52

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.060		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: rs1064795526; hg19: chr3-37035023;