Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PS1_ModeratePM1PM2PM5PP3_Strong
The ENST00000231790.8(MLH1):c.184C>A(p.Gln62Lys) variant causes a missense change involving the alteration of a 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 Lovd as Pathogenic (no stars). Another nucleotide change resulting in same amino acid change has been previously reported as Likely pathogenicin UniProt. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Q62P) has been classified as Likely pathogenic.
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]
Verdict is Pathogenic. Variant got 12 ACMG points.
PS1
Transcript ENST00000231790.8 (MLH1) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in UniProt
PM1
In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 16 uncertain in ENST00000231790.8
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr3-36996687-A-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 1466786.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=1, Uncertain_significance=1}.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.97