Parkinsonism in Childhood, a Clue to Autosomal Recessive <scp>ADCY5</scp> ‐Related Movement Disorder?

BACKGROUND: Advances in genetic testing have allowed for refined phenotypic categorization of pediatric-onset genetic movement disorders. ADCY5-related movement disorder is among this group of conditions for which we have begun to better understand a genotype-phenotype correlation. CASES: This case series details the clinical course of three biological brothers with autosomal recessively inherited biallelic variants in the ADCY5 gene. Each brother demonstrates a varied severity and combination of mixed movement disorder phenomenology, including parkinsonism, dystonia, and myoclonus exemplified in videos. CONCLUSION: The phenotype classically associated with ADCY5-related movement disorders, particularly when inherited recessively, should be expanded to include a wider spectrum of severity as well as early-onset parkinsonism. Adjusting the classically recognized phenotype in this way will help to prevent delays to genetic testing, diagnosis, and treatment while informing prognostic counseling.