A 15-mo-old boy, previously in good health, presented with recurrent episodes of projectile vomitings (3–4 per day) and mal-alignment of eyes for 1 wk. There was also a history of irritability and lethargy for 2 d. He was predominantly breastfed, and his mother was a strict vegetarian. Examination revealed marked pallor, sparse hair, and hyperpigmentation over knuckles and dorsum of toes (Fig. 1A & B). His head circumference was 47.5 cm (+0.02 Z score), and anterior fontanelle was closed. He had left paralytic esotropia secondary to left sixth nerve palsy. Fundus examination showed bilateral papilledema. The skull radiograph revealed a copper beaten appearance and Magnetic Resonance Imaging (MRI) brain revealed flattening of the posterior sclera, partial empty sella, and diffuse cerebral atrophy with thinning of corpus callosum (Fig. 2A-C). He had an elevated cerebrospinal fluid (CSF) opening pressure (310 mm of H2O; normal: 120 to 280 mm of H2O). CSF was acellular with normal biochemistry. Investigations revealed macrocytic anemia (hemoglobin–8.8 g/dl) and low serum vitamin B12 levels (210 pg/ml; normal: 251–911) and elevated blood homocysteine levels (22.79 micromol/L; normal: 3.3–11.3). Maternal serum homocysteine was elevated (24.91 micromol/L) suggestive of B12 deficiency in the mother. The serum vitamin D levels and serum ferritin levels were normal. A diagnosis of vitamin B12 deficiency associated pseudotumor cerebri was kept and the child was started on oral acetazolamide and intramuscular hydroxycobalamin at appropriate doses. His squint and vomitings resolved within a week, and activity improved. His papilledema resolved over the next 4 wk. His repeat homocysteine was 9.3 micromol/L, and that of the mother was 7.6 micromol/L which became normal after therapy.