Case series identifies MSH2 variants in three families suspected of Lynch syndrome

This research article describes a case series investigating three families with suspected Lynch syndrome. The study used genetic screening via whole-exome sequencing and immunohistochemical analysis to characterize pathogenic variants in the MSH2 gene, with no comparator group reported. The population consisted of three families, though the clinical setting was not specified.

In Family 1, researchers identified the missense variant NM_000251.3:c.2633A>T:p.E878V, which was classified as a variant of uncertain significance. Family 2 had the missense variant NM_000251.3:c.998G>A:p.C333Y, confirmed as pathogenic. Family 3 showed a novel frameshift deletion, NM_000251.3:c.507del:p.Q170Rfs*4, identified as a pathogenic variant. No effect sizes, absolute numbers, p-values, or confidence intervals were reported for these findings.

Safety and tolerability data were not reported. The study has several important limitations: it included only three families, providing a very small sample size; it was an observational case series design without statistical testing; and it reported no clinical outcome data for affected individuals. The authors note this provides experimental evidence for precision screening and genetic counseling, but causation was not established.

For clinical practice, these findings should be interpreted with caution. The identification of specific MSH2 variants, including one novel pathogenic variant, in suspected Lynch syndrome families adds to the genetic characterization of this condition. However, the extremely limited sample size and lack of clinical correlation mean these results are preliminary. Clinicians should await confirmation from larger, more robust studies before applying these specific genetic findings to counseling or management decisions.