# Fetal Rapid Eye Movement Sleep Dysfunction as a Potential Early Indicator for NALCN‐Related CLIFAHDD Syndrome: A Case Report

## TL;DR

This case report suggests that fetal REM sleep dysfunction could be an early sign of CLIFAHDD syndrome, a condition caused by NALCN gene variants.

## Contribution

The study identifies fetal REM sleep and heart rate patterns as potential early indicators of CLIFAHDD syndrome.

## Key findings

- Absent REM cycling and low fetal heart rate variability were observed in a fetus with CLIFAHDD syndrome.
- These findings suggest autonomic and sleep state dysregulation in affected fetuses.
- REM sleep loss may contribute to neurodevelopmental issues in CLIFAHDD syndrome.

## Abstract

What's already known about this topic?◦
NALCN variants, especially gain‐of‐function variants, increase neuronal excitability and reduce REM sleep.◦CLIFAHDD syndrome, caused by NALCN gain‐of‐function variants, includes congenital contractures, hypotonia, and developmental delay.What does this study add?◦This report provides detailed prenatal documentation of absent REM‐associated cycling and extremely low fetal heart rate (FHR) variability in a fetus with CLIFAHDD syndrome.◦We demonstrated the absence of FHR variability and REM sleep cycling as potential early indicators of autonomic and sleep state dysregulation.◦REM sleep loss may contribute to neurodevelopmental abnormalities in affected fetuses.

What's already known about this topic?

NALCN variants, especially gain‐of‐function variants, increase neuronal excitability and reduce REM sleep.

CLIFAHDD syndrome, caused by NALCN gain‐of‐function variants, includes congenital contractures, hypotonia, and developmental delay.

What does this study add?

This report provides detailed prenatal documentation of absent REM‐associated cycling and extremely low fetal heart rate (FHR) variability in a fetus with CLIFAHDD syndrome.

We demonstrated the absence of FHR variability and REM sleep cycling as potential early indicators of autonomic and sleep state dysregulation.

REM sleep loss may contribute to neurodevelopmental abnormalities in affected fetuses.