Striatal dysfunction in X-linked dystonia-parkinsonism is associated with disease progression

Area of Science:

• Neuroscience
• Genetics
• Radiology

Background:

• X-linked dystonia-parkinsonism (XDP) is an inherited neurodegenerative disorder affecting the basal ganglia.
• Striatal atrophy is a hallmark of XDP, but the role of the dopaminergic system in parkinsonism is not fully understood.

Purpose of the Study:

• To investigate pre- and post-synaptic dopaminergic function in patients with XDP.
• To determine if nigrostriatal dysfunction contributes to parkinsonism in XDP.

Main Methods:

• Dopamine transporter (DAT) imaging using ioflupane (FP-CIT) SPECT.
• Dopamine D2/D3 receptor imaging using 123Iodine-benzamide (IBZM) SPECT.
• Structural MRI was performed on patients and healthy controls.

Main Results:

• IBZM SPECT revealed reduced post-synaptic dopamine receptor uptake in the caudate nucleus and putamen in 8/9 symptomatic XDP patients.
• Reduced IBZM binding correlated with longer disease duration.
• FP-CIT SPECT showed slightly reduced dopamine transporter uptake, potentially related to basal ganglia volume loss.

Conclusions:

• Functional decline in post-synaptic dopaminergic neurotransmission is linked to disease duration and neurodegeneration in XDP.
• Striatal dysfunction, evidenced by cell loss, is likely the primary cause of both parkinsonism and dystonia in XDP.