Infantile Vitamin B12 deficiency commonly called Infantile tremor syndrome (ITS) is a neurocutaneous disorder primarily affecting exclusively breastfed infants of vegetarian mothers. Few reports of structural neuroimaging in this condition highlight cerebral and corpus callosal atrophy, while microstructural brain changes remain underexplored. This study investigates brain microstructural changes in Infantile Vitamin B12 deficiency using diffusion tensor imaging (DTI) and their correlation with neurodevelopmental outcomes following B12 supplementation.

Thirty children with Infantile vitamin B12 deficiency underwent clinical, neurodevelopmental, and DTI assessments at baseline and post-B12 treatment (3 months or later). MRI scans were analysed for fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) using both region-of-interest (ROI) and voxel-based approaches. Correlations between DTI metrics and developmental scores were evaluated.

Vitamin B12 supplementation significantly improved serum B12, hemoglobin, neurodevelopmental scores and normalized homocysteine levels. DTI revealed increased FA and reduced MD, RD, and AD, indicating remyelination and axonal recovery. Corpus callosum, corona radiata, and internal capsule showed maximal improvement, aligning with recovery remyelination. Grey matter areas, including the thalamus and pre-central gyrus, also demonstrated recovery. Developmental scores positively correlated with DTI metrics, particularly in regions associated with language and motor function.

Infantile vitamin B12 deficiency is characterized by global brain microstructural abnormalities that improve significantly with B12 therapy. DTI metrics correlate with neurodevelopmental recovery, underscoring the role of B12 in brain myelination.