[P1-180] MRI findings in infantile fulminant SSADH deficiency
<Introduction> Succinic semialdehyde dehydrogenase (SSADH) deficiency is a rare autosomal recessive organic-acidopathy. The subjects show variable combinations of nonspecific, non-progressive neurodevelopmental abnormalities, such as hypotonia, dystonia and seizure, mostly in infancy or childhood. In recent years, the number of reports on infantile case with fulminant clinical course is increasing, however, the neuroradiological characteristics in such cases were not fully described. <Case Report> An 8 months-old boy presented to our department for evaluation of repetitive focal seizures since the age of 5 month. The initial evaluation was static encephalopathy characterized by global developmental delay with hypotonia, normal interictal EEG and normal cerebral MRI. At the 9th month, he started to repeat acute encephalopathy-like episodes characterized by status epilepticus, coma, tachycardia and subsequent neurodevelopmental regression. The cerebral MRI showed abnormal intensities in globus pallidus, putamen, temporal/insular/frontal cortex and white matter, especially in fornix and cerebral peduncle. Notable asymmetry and heterogeneous signal intensity of the lesions initially suggested other pathologies, for example vascular and demyelinating one, than neurometabolic disorders. However, the neuroradiological analogy for one of the previous reports on infantile fulminant SSADH deficiency promoted us to repeat the analysis of urine organic-acids, and the final diagnosis of SSADH deficiency was confirmed by detection of urine 4-hydroxybutylate and compound heterozygous ALDH5A1 mutations. <Discussion> The abnormal intensity in the nucleus of basal ganglia and brain stem can be asymmetrical and heterogeneous. White matter abnormalities can be observed also in fornix and cerebral peduncles. These observations can differentiate SSADH deficiency from other infantile neurometabolic disorders.