To present a case of treatable dystonia, initially diagnosed as cerebral palsy, related to two novel variants of the SHQ1 gene.

Dystonia is frequently under-recognized, difficult to treat once identified, and infrequently genetically characterized. Reporting cases of treatable dystonia linked to novel genetic mutations may clarify the pathway for diagnosing and treating similar cases. Exploration of the downstream physiological impacts of these mutations may add to our understanding of the molecular fingerprints of levodopa-responsive dystonia.

A 15-year-old boy presented for second opinion of chronic adventitious movements. He was abandoned as a child and recovered at 11 months of age. He was noted at age 5 to have persistent global developmental delay. At age 7 he was observed to have progressive difficulty with walking, general coordination, motion sickness, and recurrent falls. Exam revealed diffuse hypertonia, hyperreflexia, and abnormal gait. Per records, he was diagnosed with athetoid cerebral palsy.

At age 15, he was first evaluated by a movement disorders neurologist. He was observed to have dystonia and chorea. Genetic testing was sent and he was started on trihexyphenidyl then carbidopa-levodopa. Genetic testing revealed two heterozygous variants of unknown significance in the SHQ1 gene: c.114dup (p.K39Qfs*23) and c.443 A>G (p.Y148C). These are considered likely to be pathogenic due to other reports of levodopa-responsive dystonia associated with different variants of the SHQ1 gene. In follow-up, the patient’s symptoms had improved in response to medication.

Other cases of SHQ1 related dystonia have been identified, with similar symptoms, levodopa-responsiveness, and evidence of low dopamine and serotonin precursors in the CSF. In one case, treatment with levodopa corrected the deficiency of these precursors and partially reversed the clinical symptoms.