Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4_Moderate
The NM_001258281.1(MSH2):c.-132T>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 0.0000491 in 834,410 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 (★).
MSH2 (HGNC:7325): (mutS homolog 2) This locus is frequently mutated in hereditary nonpolyposis colon cancer (HNPCC). When cloned, it was discovered to be a human homolog of the E. coli mismatch repair gene mutS, consistent with the characteristic alterations in microsatellite sequences (RER+ phenotype) found in HNPCC. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Apr 2012]
⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.000143
AC:
3
AN:
20920
American (AMR)
AF:
0.00
AC:
0
AN:
35004
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
21728
East Asian (EAS)
AF:
0.0000301
AC:
1
AN:
33210
South Asian (SAS)
AF:
0.00
AC:
0
AN:
67592
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
33520
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
3044
European-Non Finnish (NFE)
AF:
0.0000621
AC:
36
AN:
579610
Other (OTH)
AF:
0.0000251
AC:
1
AN:
39782
⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.
The c.-118T>G variant is located in the 5' untranslated region (5’ UTR) of the MSH2 gene. This variant results from a T to G substitution 118 bases upstream from the first translated codon. This nucleotide position is highly conserved in available vertebrate species. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -