ADCY5-related Dyskinesia: a Treatable Inherited Neurometabolic Disorder

Case Report. A 40-year-old Brazilian man presented with long-standing loss of balance, dystonia, and choreoathetosis, with episodic paroxysmal worsening. Neuroimaging and cerebrospinal fluid analysis were both unremarkable. Quantitative urine organic acid analysis, plasma acylcarnitine quantitative profile, and quantitative analysis of plasma amino acids by high performance liquid chromatography were all within normal interval values. Multigene next-generation sequencing panel identified the heterozygous pathogenic variant c.1252C>T (p.Arg418Trp) in the ADCY5 gene, defining a diagnosis of ADCY5-related dyskinesia. Oral caffeine was associated to clonazepam and provided marked improvement of motor symptoms. Conclusion. This report adds evidence to the safety and efficacy of caffeine in the treatment of genetically confirmed cases of ADCY5-related dyskinesia in the context of gain-of-function variants.