Selective Serotonin Reuptake Inhibitor Treatment Post Gene Therapy for an Ultrarare Neurometabolic Disorder (AADC Deficiency).

A 7-year-old girl presented with persistent anxiety symptoms for several years following gene therapy for an ultrarare neurometabolic disorder (aromatic L-amino acid decarboxylase [AADC] deficiency). AADC is the final enzyme in the monoamine synthesis pathway (Figure 1). Its absence results in a severe combined deficiency in serotonin, dopamine, epinephrine, and norepinephrine, causing significant developmental delays, hypotonia, and dystonia. The incidence of AADC deficiency is estimated at ∼1 in 500,000, and ∼200 cases have been described. Recently available disease-modifying gene therapy for this condition dramatically improves motor symptoms, and received regulatory approval in some regions in 2022. There are no data to guide psychiatric care post gene therapy for AADC or other neurologic disorders to date..