Neuroimaging

Imaging findings in Riboflavin Transporter Deficiency (RTD) are variable.

Brain MRI

In data obtained from the Cure RTD Foundation International Registry, and those obtained from published literature, a brain MRI was noted for 69 patients (55 RTD Type 2 and 14 RTD Type 3).

RTD Type 2

In general the brain MRI was found to be normal with abnormalities of unknown significant being reported in only 5 of 55 (9%) RTD Type 2 patients.  Abnormalities observed included mild atrophy of the optic chiasm and anterior superior cerebellar vermis.

RTD Type 3

Amoung RTD Type 3 patients, 4 of the 14 (28%) reported brain MRI abnormalities, which included T2 hyperintensities in the brainstem and/or brainstem nuclei and atrophy of the brainstem and cerebellum.

MRI images of spine

MRI images of the spine have rarely been reported in genetically confirmed RTD cases.  One individual with RTD Type 2 (Woodcock et al. 2017) and one individual with RTD Type 3 (Spagnoli et al. 2012) have been reported with T2 hyperintensity and diffusion tensor imaging signal abnormalities in the dorsal columns of the spinal cord.  These signal abnormalities were hypothesized to reflect active degeneration of sensory pathways in these children as they were imaged during a period of rapid sensorimotor decline.  In addition, Woodcock and colleagues (2017) provided the first report of contrast enhancement of the ventral nerve roots of the cauda equine, suggesting a process affecting predominantly anterior horn cells in a child with RTD Type 2.

References

Spagnoli C, De Sousa C (2012) Brown-Vialetto-Van Laere syndrome and Fazio-Londe disease – treatable motor neuron diseases of childhood. Dev Med Child Neurol 54:292–3

Woodcock IR, Menezes MP et al (2017) Genetic, Radiologic and Clinical Variability in Brown-Vialetto-Van Laere Syndrome. Seminars in Pediatric Neurology DOI: http://dx.doi.org/10.1016/j.spen.2017.03.001