# Recessive Loss of PI4K2A Function Causes a Developmental and Epileptic Dyskinetic Encephalopathy with Prominent Orolingual Dyskinesia

## TL;DR

This paper shows that a specific gene defect causes a neurological disorder with distinctive mouth and tongue movements, which is often overlooked in other similar conditions.

## Contribution

Highlights orolingual dyskinesia as a core feature of PI4K2A-related disorder and emphasizes its diagnostic importance.

## Key findings

- All individuals with PI4K2A deficiency exhibited orolingual dyskinesia along with developmental and movement issues.
- Orolingual dyskinesia is under-recognized in other neurodevelopmental disorders.

## Abstract

Biallelic loss‐of‐function variants in PI4K2A have been associated with a neurodevelopmental disorder characterized by seizures and movement disorders, including orofacial dyskinesia. However, only 4 cases have been reported. Orolingual dyskinesia—defined as involuntary movements of the mouth and tongue—is observed in various pediatric neurodevelopmental disorders (NDD) but remains under‐recognized.

The aims were to highlight orolingual dyskinesia as a core feature of PI4K2A‐related disorder (PI4K2A‐RD) and explore its presence across other NDDs.

We described two new families with PI4K2A‐RD and reviewed the clinical features of four previously reported cases. A focused literature search was also conducted to identify other neurogenetic conditions associated with orolingual dyskinesia.

All individuals with PI4K2A deficiency exhibited orolingual dyskinesia, along with developmental delay, movement abnormalities, and variable seizures. The literature review confirmed frequent underreporting of this feature in NDDs.

Orolingual dyskinesia is a relevant but under‐recognized clinical sign in PI4K2A‐RD and other neurogenetic conditions, with potential diagnostic value. © 2025 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.