Brain & development
June 12, 2026 · via Europe PMC
Periodic limb movements during sleep in Lesch-Nyhan syndrome.
Saito Y, Sumitomo N, Saito T, Kimura A, Fukumizu M, Asato S, Kodama K, Matsui K.
AI summary — for doctors, generated from the abstract only
A small case series of 3 children with Lesch-Nyhan syndrome found that periodic limb movements during sleep preceded the onset of self-injurious behavior, leading the authors to propose that both phenomena may stem from a shared underlying dopaminergic imbalance affecting sensory processing.
What was studied
A case series of three children (ages 2-7) with Lesch-Nyhan syndrome (LNS) characterized periodic limb movements during sleep (PLMS), diagnosed clinically in one patient and by polysomnography in two, examining the movement patterns, timing relative to self-injurious behavior onset, and polysomnographic features.
Key findings
- Repetitive, clustered movements involving upper and lower extremities were first observed between ages 1 and 5 in each child, preceding the onset of self-injurious behavior characteristic of Lesch-Nyhan syndrome
- Movement patterns consisted of flexion or combined flexion/extension of all four limbs, with muscle contraction duration of 0.5-5 seconds and inter-movement intervals of 5-20 seconds
- Polysomnography confirmed these as periodic limb movements during sleep, occurring predominantly during N1 sleep stage, with PLMS indices of 6.9 and 8.8 events per sleep hour in the two patients studied by PSG
Clinical relevance
The findings suggest that periodic limb movements during sleep may be an early, underrecognized sign preceding self-injurious behavior in Lesch-Nyhan syndrome, and the authors propose both may arise from a shared dopaminergic imbalance affecting sensory gating across cortico-striatal, trigeminal, and spinal systems, which could be a useful early clinical marker to monitor and may inform future mechanistic research into self-injurious behavior in this condition.
Who should care
Limitations
This is a very small case series (3 patients) with a proposed mechanistic hypothesis (dopaminergic imbalance and sensory gating) that is speculative and not directly tested in this study, so these findings cannot establish causality or be generalized to predict self-injurious behavior onset in other LNS patients.
In this small case series, periodic limb movements during sleep preceded self-injurious behavior in children with Lesch-Nyhan syndrome, leading the authors to propose a shared dopaminergic sensory-gating mechanism linking the two phenomena, a hypothesis warranting further research.
This is an AI-generated summary of the published abstract, not a clinical recommendation. It may not reflect the full text or subsequent updates — verify against the original source before acting on it.
Abstract
Aim
To characterize the periodic limb movements during sleep (PLMS) in children with Lesch-Nyhan syndrome (LNS).
Methods
Three subjects with LNS aged 2 to 7 years were enrolled. PLMS was diagnosed clinically in one patient, and based on polysomnography (PSG) in two.
Results
Repetitive, clustered movements during sleep, involving upper and lower extremities, were first observed in each child between 1 and 5 years of age, preceding the onset of self-injurious behaviors (SIB) characteristic of LNS. The movement patterns consisted of either flexion, or a combination of flexion and extension, of all four limbs. Duration of muscle contraction ranged from 0.5 to 5 s, with inter-movement intervals generally of 5 to 20 s. PSG qualified these movements as PLMS, by demonstration of four or more movements in clusters, occurring predominantly during N1 sleep stage. The PLMS index was 6.9 and 8.8 events per sleep hour for each patient.
Interpretation
PLMS may represent impaired spinal sensory gating in LNS, potentially resulting from reduced dopaminergic activity and/or dopamine receptor hypersensitivity. We propose that SIB in LNS constitutes a maladaptive motor response to aberrant sensory processing or dysesthesia, arising from dopaminergic imbalance across cortico-striatal, trigeminal, and spinal gating systems.
DOI
10.1016/j.braindev.2026.104560
PMID
42284792
Research metadata (titles, abstracts, authors, publication dates) is sourced from Europe PMC, which aggregates content from PubMed/MEDLINE, PubMed Central, and other providers under the U.S. National Library of Medicine (NLM/NCBI). NLM does not claim copyright on abstracts; the original journal publishers or authors may hold rights to the full articles. AI-generated summaries are derived only from the abstract, never the full text, and are always labeled as AI-generated.
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