Infantile Vitamin B12 Deficiency with Reversible Acquired Vision Loss

To the Editor: We report three children (two boys, one girl) with developmental delay and acquired vision loss. They presented with loss of ability to visually fixate and follow for 2-4 wk (2, 3, 4 wk respectively). All babies were exclusively breast fed by vegetarian mothers. On examination, they had skin and hair changes reminiscent of the "infantile tremor syndrome". They had no visual fixation or tracking. Pupils were normally reacting to light. They had temporal disc pallor on fundus examination. Their serum vitamin B12 levels (normal >211 pg/ml) were low (68, 144, 92 pg/ml), while plasma homocysteine was high (44, 90, 48 mmol/L). Their MRI brains showed frontotemporal dominant cortical atrophy and thinning of corpse callosum of varying severity. The P100 latency on visually evoked potentials was prolonged in all. Two of the mothers tested were also found to be vitamin B12 deficient. The children were treated with injection hydroxocobalamin 1 mg/d for 2 wk. The follow up vitamin B12 and homocysteine levels were normal. The babies recovered visual fixation and following by 4 wk of treatment. All had recovery in developmental milestones at their last follow up more than a year after treatment. …