Scoping Review on ADCY5-Related Movement Disorders

Pearls & Oy-sters: ADCY5-Related Dyskinesia: From a Longstanding Misdiagnosis of Drug-Resistant Epilepsy

ADCY5-related dyskinesia (ADCY5-RD) is a hyperkinetic movement disorder of childhood onset, resulting from pathogenic variants in the ADCY5 gene. Paroxysmal worsening of the movements and movements that occur in relation to sleep and/or awakenings are hallmarks of ADCY5-RD. ADCY5-RD is therefore often misdiagnosed as sleep-related hypermotor epilepsy, sleep disorders, paroxysmal hyperkinesias, childhood onset chorea, or psychogenic events. In this case, a 59 year-old woman with a longstanding misdiagnosis of drug-resistant epilepsy was ultimately diagnosed with ADCY5-RD following video EEG. She had been followed for paroxysmal episodes of nonvoluntary movements mostly occurring during sleep since 2 years of age. She also exhibited continuous progressive dysarthria and axial hypotonia. Episodic orofacial dystonia was present as well. For 57 years, these symptoms had been treated with various combinations of antiseizure medications. However, the diagnosis was reconsidered when prolonged video-EEG monitoring recorded sleep-onset nonepileptic events, starting during N1 and N2 stages of NREM sleep. Genetic testing of ADCY5 confirmed the diagnosis. Caffeine and progressive withdrawal of antiseizure medications except clonazepam resulted in clinical improvement in paroxysms, which became less intense and less frequent. Given that ADCY5-RD was first described in 2012, there may be more adult patients misdiagnosed in childhood. Thus, we recommend considering alternative diagnosis for adult patients with paroxysmal sleep-related events to detect ADCY5-RD in adults. Although there are still no treatment guidelines for ADCY5-RD, adenosine-2A receptor antagonists have emerged as a promising therapeutic option.

Treatment Efficacy of Theophylline in ADCY5-Related Dyskinesia: A Retrospective Case Series Study

BACKGROUND

ADCY5-related dyskinesia is a rare disorder caused by mutations in the ADCY5 gene resulting in abnormal involuntary movements. Currently, there are no standardized guidelines to treat this condition.

OBJECTIVE

The aim of this study was to evaluate the efficacy of theophylline administration in improving symptoms and quality of life in patients with ADCY5-related dyskinesia.

METHODS

A retrospective study was conducted involving 12 patients (aged 2-41 years) with ADCY5-related dyskinesia. Participants completed a questionnaire about theophylline administration, including dosage, improvement of symptoms, adverse effects, and changes in quality of life. Data were analyzed for reported efficacy and side effects.

RESULTS

Theophylline administration demonstrated substantial efficacy, with 92% (11 of 12) of patients reporting significant improvements in their movement disorders. The average improvement score was 7.0 ± 1.9 (mean ± SD) on a 10-point scale. Notable improvements included reductions in severity and frequency of episodes, improved gait, more independent mobility, psychosocial well-being, and quality of sleep. Adverse effects were reported by 6 patients, including dystonia, worsening of speech, headaches, nausea, impaired sleep, and agitation.

CONCLUSIONS

Theophylline shows substantial promise as a treatment option for ADCY5-related dyskinesia, improving various aspects of patients' quality of life and movement disorder symptoms. Further research is needed to optimize dosing, to understand long-term effects, and to explore combinational drug therapies. Despite the small cohort size and the retrospective nature of this study, the results support theophylline administration to decrease dyskinetic movements and enhance overall quality of life in patients. © 2025 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Atypical ADCY5-related movement disorders: Highlighting adolescent/adult-onset cervical dystonia

BACKGROUND

ADCY5-related movement disorders are typically paroxysmal dyskinesia (PxDs) and/or static hyperkinetic movement disorders. Nocturnal paroxysmal dyskinesia (PxD), facial or perioral dyskinesia are suggestive of this genetic diagnosis. Next generation sequencing has enabled an expansion of the ADCY5- related phenotype.

OBJECTIVE

The aim of our study was to report atypical phenotypes.

RESULTS

We describe 13 patients from 8 different families, of which 10 had adolescent/adult-onset head and upper limb tremor followed by static cervical dystonia without PxD. We report three novel ADCY5 variants in these patients, located in the catalytic domains, close to previously reported variants. Caffeine was ineffective for the 3 patients who tried the treatment, and botulinum toxin therapy seemed to be the most effective treatment. We also describe 2 patients with spontaneous remission of pediatric-onset PxD before adulthood.

CONCLUSION

We highlight an adolescent/adult-onset phenotype with head tremor and cervical dystonia, widening the genetic spectrum of cervical dystonia. Moreover, we broaden the pediatric ADCY5-PxD phenotype, highlighting previously unreported cases of spontaneous remission.

Exploring the Genetic Landscape of Chorea in Infancy and Early Childhood: Implications for Diagnosis and Treatment

Chorea is a hyperkinetic movement disorder frequently observed in the pediatric population, and, due to advancements in genetic techniques, an increasing number of genes have been associated with this disorder. In genetic conditions, chorea may be the primary feature of the disorder, or be part of a more complex phenotype characterized by epileptic encephalopathy or a multisystemic syndrome. Moreover, it can appear as a persistent disorder (chronic chorea) or have an episodic course (paroxysmal chorea). Managing chorea in childhood presents challenges due to its varied clinical presentation, often involving a spectrum of hyperkinetic movement disorders alongside neuropsychiatric and multisystemic manifestations. Furthermore, during infancy and early childhood, transient motor phenomena resembling chorea occurring due to the rapid nervous system development during this period can complicate the diagnosis. This review aims to provide an overview of the main genetic causes of pediatric chorea that may manifest during infancy and early childhood, focusing on peculiarities that can aid in differential diagnosis among different phenotypes and discussing possible treatment options.

Emerging therapies for childhood-onset movement disorders

PURPOSE OF REVIEW

We highlight novel and emerging therapies in the treatment of childhood-onset movement disorders. We structured this review by therapeutic entity (small molecule drugs, RNA-targeted therapeutics, gene replacement therapy, and neuromodulation), recognizing that there are two main approaches to treatment: symptomatic (based on phenomenology) and molecular mechanism-based therapy or 'precision medicine' (which is disease-modifying).

RECENT FINDINGS

We highlight reports of new small molecule drugs for Tourette syndrome, Friedreich's ataxia and Rett syndrome. We also discuss developments in gene therapy for aromatic l-amino acid decarboxylase deficiency and hereditary spastic paraplegia, as well as current work exploring optimization of deep brain stimulation and lesioning with focused ultrasound.

SUMMARY

Childhood-onset movement disorders have traditionally been treated symptomatically based on phenomenology, but focus has recently shifted toward targeted molecular mechanism-based therapeutics. The development of precision therapies is driven by increasing capabilities for genetic testing and a better delineation of the underlying disease mechanisms. We highlight novel and exciting approaches to the treatment of genetic childhood-onset movement disorders while also discussing general challenges in therapy development for rare diseases. We provide a framework for molecular mechanism-based treatment approaches, a summary of specific treatments for various movement disorders, and a clinical trial readiness framework.

Neurological presentations of inborn errors of purine and pyrimidine metabolism

Purines and pyrimidines are essential components as they are the building blocks of vital molecules, such as nucleic acids, coenzymes, signalling molecules, as well as energy transfer molecules. Purine and pyrimidine metabolism defects are characterised by abnormal concentrations of purines, pyrimidines and/or their metabolites in cells or body fluids. This phenomenon is due to a decreased or an increased activity of enzymes involved in this metabolism and has been reported in humans for over 60 years. This review provides an overview of neurological presentations of inborn errors of purine and pyrimidine metabolism. These conditions can lead to psychomotor retardation, epilepsy, hypotonia, or microcephaly; sensory involvement, such as deafness and visual disturbances; multiple malformations, as well as muscular symptoms. Clinical signs are often nonspecific and thus overlooked, but some diseases are treatable and early diagnosis may improve the child's future. Although these metabolic hereditary diseases are rare, they are most probably under-diagnosed. When confronted with suggestive clinical or laboratory signs, clinicians should prescribe genetic testing in association with a biochemical screening including thorough purine and pyrimidine metabolites analysis and/or specific enzyme evaluation. This is most likely going to increase the number of confirmed patients.

Clinical Reasoning: A 3-Year-Old Boy With Abnormal Movements During Sleep

We report a case of a 3-year-old boy who presented with abnormal movements that initially occurred only during sleep. Three years later, he went on to develop hyperkinetic movements during the daytime while awake. There was a strong family history of various paroxysmal neurologic disorders. In this report, we discuss the clinical approach, differential diagnosis, investigation, and treatment options for nocturnal hyperkinetic movements and paroxysmal movement disorders.