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Periodic limb movements during sleep in Lesch-Nyhan syndrome
Yoshiaki Saito1, Noriko Sumitomo2, Takashi Saito2
1Department of Pediatrics, National Rehabilitation Center for Children with Disabilities, Tokyo, Japan.
Brain & Development
|June 12, 2026
Summary
Periodic limb movements during sleep (PLMS) in children with Lesch-Nyhan syndrome (LNS) involve repetitive limb movements before self-injurious behaviors (SIB). These movements may stem from impaired spinal sensory gating due to dopamine system dysfunction.
Area of Science:
- Neurology
- Pediatrics
- Sleep Medicine
Background:
- Lesch-Nyhan syndrome (LNS) is a rare genetic disorder characterized by neurological and behavioral abnormalities.
- Self-injurious behaviors (SIB) are a hallmark of LNS, but their underlying mechanisms are not fully understood.
Purpose of the Study:
- To investigate and characterize periodic limb movements during sleep (PLMS) in children diagnosed with LNS.
- To explore the potential relationship between PLMS and the development of SIB in LNS.
Main Methods:
- Study included three pediatric subjects with LNS, aged 2 to 7 years.
- PLMS diagnosis was based on clinical observation in one child and polysomnography (PSG) in two.
- Detailed analysis of movement patterns, duration, and sleep stage distribution was performed.
Main Results:
- Repetitive, clustered limb movements (flexion or flexion-extension) were observed in all subjects between 1 and 5 years of age, preceding SIB.
- Polysomnography confirmed these movements as PLMS, predominantly occurring during the N1 sleep stage.
- The PLMS index ranged from 6.9 to 8.8 events per sleep hour.
Conclusions:
- PLMS in LNS may indicate impaired spinal sensory gating, potentially linked to dopaminergic system abnormalities.
- SIB in LNS could be a maladaptive motor response to aberrant sensory processing or dysesthesia resulting from dopamine imbalance.
- Further research into dopaminergic pathways and sensory processing in LNS is warranted.
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