NEDHSIL (Neurodevelopmental Disorder with Hypotonia, Stereotypic Hand Movements, and Impaired Language)

**What it means:** NEDHSIL is the **alternative name** for MEF2C-associated syndrome. It describes the core clinical features without naming the gene. You might see it in older papers or clinical notes. **Why the different names:** Medical genetics sometimes names syndromes descriptively (by what they look like) before the gene is discovered. It's like calling "Type 1 Diabetes" "Juvenile Onset Diabetes" — the descriptive name came first, and the genetic cause was identified later. NEDHSIL = MEF2C deficiency. They're the same condition, just named differently.