SERIAL MRI AND SPECT FINDINGS IN A SEVERE INFANTILE FORM OF DRPLA

Objectives: Dentatorublar-pallidoluysian atrophy (DRPLA) is a rare and autosomal-dominant neurodegenerative disorder. Clinical symptoms depend on age of onset and number of CAG repeats. We previously reported 2 patients with a severe infantile form of DRPLA who presented with dystonia, very early deterioration, early onset (˜6 months), and the presence of extremely long CAG repeats (93 and 90 base pairs, respectively). Here, we review the neuroradiological findings to clarify our diagnosis of these patients.

Methods: MRI and single-photon emission CT (SPECT) findings in the two study patients were retrospectively reviewed. MRI was obtained at 2 and 4 years of age in both patients, and all results were compared. In addition, the SPECT results were compared with the standard SPECT database established in our institute, and with findings in other disorders (late infantile form of neuronal ceroid-lipofuscinosis (NCL) and infantile neuroaxonal dystrophy (INAD)).

Results: Serial MRI showed progressive atrophy especially in the frontal lobes, brain stem, and cerebellum. T2- weighted images showed high signal intensity in the globus pallidus at 2 years of age, and in the deep white matter at 4 years of age. The SPECT findings disclosed more severe hypoperfusion in the frontal lobes and cerebellum than observed in other neurodegenerative disorders.

Conclusion: We could not make a precise diagnosis for these patients, despite the high signal intensity of the deep white matter and progressive severe atrophy in the frontal lobes, brain stem, and cerebellum on MRI suggesting several progressive disorders. The SPECT findings were unique in showing severe hypoperfusion in the frontal lobes and cerebellum. These findings will be of value to others in diagnosing the rare disorder, severe infantile form of DRPLA.