In:
Journal of Medical Genetics, BMJ, Vol. 57, No. 5 ( 2020-05), p. 308-315
Kurzfassung:
Inactivating mutations in the MLH1 DNA mismatch repair (MMR) gene underlie 42% of Lynch syndrome (LS) cases. LS is a cancer predisposition causing early onset colorectal and endometrial cancer. Nonsense and frameshift alterations unambiguously cause LS. The phenotype of missense mutations that only alter a single amino acid is often unclear. These variants of uncertain significance (VUS) hinder LS diagnosis and family screening and therefore functional tests are urgently needed. We developed a functional test for MLH1 VUS termed ‘oligonucleotide-directed mutation screening’ (ODMS). Methods The MLH1 variant was introduced by oligonucleotide-directed gene modification in mouse embryonic stem cells that were subsequently exposed to the guanine analogue 6-thioguanine to determine whether the variant abrogated MMR. Resuts In a proof-of-principle analysis, we demonstrate that ODMS can distinguish pathogenic and non-pathogenic MLH1 variants with a sensitivity of 〉 95% and a specificity of 〉 91%. We subsequently applied the screen to 51 MLH1 VUS and identified 31 pathogenic variants. Conclusion ODMS is a reliable tool to identify pathogenic MLH1 variants. Implementation in clinical diagnostics will improve clinical care of patients with suspected LS and their relatives.
Materialart:
Online-Ressource
ISSN:
0022-2593
,
1468-6244
DOI:
10.1136/jmedgenet-2019-106520
Sprache:
Englisch
Verlag:
BMJ
Publikationsdatum:
2020
ZDB Id:
2009590-9
SSG:
12
