Variant of Uncertain Significance (VUS)

**What it means:** When genetic testing finds a mutation, sometimes it's unclear whether that mutation **causes** disease or is just a harmless personal variation. These uncertain results are called Variants of Uncertain Significance (VUS). It's like finding a word you don't recognize in a recipe and not knowing if it's an important ingredient or just a typo. **How episignature helps:** For many patients, genetic testing returns a VUS — they suspect MEF2C deficiency but can't prove it. The DNA methylation episignature acts as additional evidence: if the methylation pattern matches the MEF2C signature, it strongly supports the diagnosis even when the genetic variant is uncertain. This can be the difference between a family knowing what's wrong and being stuck in diagnostic limbo.