PDE10A and ADCY5 mutations linked to molecular and microstructural basal ganglia pathology

Background Striatal cyclic adenosine monophosphate activity modulates movement and is determined from the balance between its synthesis by adenylate cyclase 5 (ADCY5) and its degradation by phosphodiesterase 10A (PDE10A). Objective We assessed the integrity of striatocortical pathways, in vivo, in 2 genetic hyperkinetic disorders caused by ADCY5 and PDE10A mutations. Methods We studied 6 subjects with PDE10A and ADCY5 mutations using [C-11]IMA107 PET, [I-123]FP-CIT Single-photon emission computed tomography (SPECT) and multimodal MRI to investigate PDE10A and dopamine transporter availability, neuromelanin-containing neurons, and microstructural white and gray matter changes, respectively. Results We found that PDE10A and ADCY5 mutations were associated with decreased PDE10A expression in the striatum and globus pallidus, decreased dopamine transporter expression in the striatum, loss of substantia nigra neuromelanin-containing neurons, and microstructural white and gray matter changes within the substantia nigra, striatum, thalamus, and frontoparietal cortices. Conclusions Our findings indicate an association between PDE10A and ADCY5 mutations and pre/postsynaptic molecular changes, substantia nigra damage, and white and gray matter changes within the striatocortical pathways. (c) 2018 International Parkinson and Movement Disorder Society