Fig. 1

Cranial MRI shows a consistent pattern of hypomyelination across ABAT patients. MRI of Subject 1 (S1) at age 9 months shows extensive T2 hyperintensity in the deep white matter that lags ~5 months behind the patient’s chronological age, suggesting diffuse mild hypomyelination. However, the anterior limb of the internal capsule is hyperintense on T1, and partially hypointense on T2, with a non-restricted ADC map. In contrast, while Subjects 2 (S2) and 3 (S3) are older at 13 and 17 months, myelination in the posterior limbs of the internal capsules is less complete and associated with restricted diffusion on ADC, suggestive of more severe hypomyelination. Additionally, Subjects 2 and 3 exhibit diffuse yet mild cerebral atrophy. Subject 3 also exhibits asymmetry with disproportionate right sided atrophy. C: caudate, P: putamen, GP: globus palidus, T: thalamus, PLIC: posterior limb of the internal capsule