Inspired by a patient
Koy A, Cirak S, Gonzalez V, Becker K, Roujeau T, Milesi C, Baleine J, Cambonie G, Boularan A, Greco F, Perrigault PF, Cances C, Dorison N, Doummar D, Roubertie A, Beroud C, Körber F, Stüve B, Waltz S, Mignot C, Nava C, Maarouf M, Coubes P, Cif L. Deep brain stimulation is effective in pediatric patients with GNAO1 associated severe hyperkinesia. J Neurol Sci. 2018 Aug 15;391:31-39.
Exacerbation of hyperkinesia is a life-threatening complication of dyskinetic movement disorders, which can lead to multi-organ failure and even to death. GNAO1 has been recently identified to be involved in the pathogenesis of early infantile epileptic encephalopathy and movement disorders. Patients with GNAO1 mutations can present with a severe, progressive hyperkinetic movement disorder with prolonged life-threatening exacerbations, which are refractory to most anti-dystonic medication.
The objective was to investigate the evolution of symptoms and the response to deep brain stimulation of the globus pallidus internus (GPi-DBS) in patients with different GNAO1 mutations.
We report six patients presenting with global motor retardation, reduced muscle tone and recurrent episodes of severe, life-threatening hyperkinesia with dystonia, choreoathetosis, and ballism since early childhood. Five of them underwent GPi-DBS.
The genetic workup revealed mutations in GNAO1 for all six patients. These encompass a new splice site mutation (c.723+1G>T) in patient 1, a new missense mutation (c.610G>C; p.Gly204Arg) in patient 2, a heterozygous mutation (c.625>T; p.Arg209Cys) in patients 3 and 4, and a heterozygous mutation (c.709G>A; p.Glu237Lys) in patients 5 and 6. By intervention with GPi-DBS the severe paroxysmal hyperkinetic exacerbations could be stopped in five patients. One patient is still under evaluation for neuromodulation.
In complex movement disorders of unsolved etiology clinical WES can rapidly streamline pathogenic genes. We identified two novel GNAO1 mutations. GPi-DBS can be an effective and life-saving treatment option for patients with GNAO1 mutations and has to be considered early.
Honey CM, Malhotra AK, Tarailo-Graovac M, van Karnebeek CDM, Horvath G, Sulistyanto A. GNAO1 Mutation-Induced Pediatric Dystonic Storm Rescue With Pallidal Deep Brain Stimulation. J Child Neurol. 2018 May;33(6):413-416.
Dystonic storm or status dystonicus is a life-threatening hyperkinetic movement disorder with biochemical alterations due to the excessive muscle contractions. The medical management can require pediatric intensive care unit admission and a combination of medications while the underlying trigger is managed. Severe cases may require general anesthesia and paralytic agents with intubation and may relapse when these drugs are weaned. Deep brain stimulation of the globus pallidum has been reported to terminate dystonic storm in several pediatric cases. We present a 10-year-old boy with a de novo GNAO1 mutation-induced dystonic storm who required a 2-month pediatric intensive care unit admission and remained refractory to all medical treatments. Deep brain stimulation was performed under general anesthetic without complication. His dyskinetic movements stopped with initiation of stimulation. He was discharged from the pediatric intensive care unit after 4 days. We present prospectively evaluated changes in dystonia symptoms and quality of life for a patient with GNAO1 mutation treated with deep brain stimulation.
Feng H, Khalil S, Neubig RR, Sidiropoulos C. A mechanistic review on GNAO1-associated movement disorder. Neurobiol Dis. 2018 Aug;116:131-141.
Mutations in the GNAO1 gene cause a complex constellation of neurological disorders including epilepsy, developmental delay, and movement disorders. GNAO1 encodes Gαo, the α subunit of Go, a member of the Gi/o family of heterotrimeric G protein signal transducers. Go is the most abundant membrane protein in the mammalian central nervous system and plays major roles in synaptic neurotransmission and neurodevelopment. GNAO1 mutations were first reported in early infantile epileptic encephalopathy 17 (EIEE17) but are also associated with a more common syndrome termed neurodevelopmental disorder with involuntary movements (NEDIM). Here we review a mechanistic model in which loss-of-function (LOF) GNAO1 alleles cause epilepsy and gain-of-function (GOF) alleles are primarily associated with movement disorders. We also develop a signaling framework related to cyclic AMP (cAMP), synaptic vesicle release, and neural development and discuss gene mutations perturbing those mechanisms in a range of genetic movement disorders. Finally, we analyze clinical reports of patients carrying GNAO1 mutations with respect to their symptom onset and discuss pharmacological/surgical treatments in the context of our mechanistic model.