123I-FP-CIT Brain SPECT Findings in Succinic Semialdehyde Dehydrogenase (SSADH) Deficiency

Abstract

Background: Succinic semialdehyde dehydrogenase (SSADH) deficiency is a rare autosomal recessive disorder. Neuroimaging findings are commonly considered rather non-specific. To date, no neuroreceptorial brain imaging with ¹²³I-FP-CIT(DaTScan) is known in subjects with SSADH deficiency.

Methods: A 30-year-old man gained our attention to rule out any potential nigrostriatal dopaminergic presynaptic pathway alterations in a clinical context of a γ-hydroxybutyric aciduria. He showed impossibility to the autonomous gait, head and trunk retropulsion, lower limbs strength deficit, verbal and upper limbs motor stereotypies and irregular eye tracking.

Results: His brain MRI depicted basal ganglia signal abnormalities. Brain SPECT with DaTSCan images showed a global significant reduction of radiotracer uptake.

Conclusions: The findings obtained by means of the ¹²³I-DaTScan brain SPECT may give rise to new concerns on pathophysiological aspects of the SSADH deficiency disorder that has never been investigated before, such as the nigrostriatal dopaminergic system's functionality, encouraging further investigation.

Keywords: 123I-FP-CIT SPECT; DaTScan; SSADH deficiency; neuroreceptorial imaging; presynaptic dopaminergic system; γ-hydroxybutyric aciduria.