SCIENTIFIC LETTER Frontotemporal Atrophy: Presenting Sign in Infantile Cobalamin Deficiency Pallavi Vats 1 & Prashant Verma 1 & Bijo Varughese 2 & Somesh Kumar 2 & Seema Kapoor 1,2 Received: 8 September 2017 /Accepted: 10 November 2017 /Published online: 23 November 2017 # Dr. K C Chaudhuri Foundation 2017 To the Editor: Infantile Cobalamin deficiency is an under rec- ognized cause of neurological morbidity in infants [1]. Here we discuss a five-month-old infant who presented with regres- sion and was referred with a possible diagnosis of Glutaric aciduria type I due to the MRI picture. A five-month-old female infant presented with loss of mile- stones over the past 20 d. The infant had subtle seizures followed by tonic clonic seizure, myoclonic jerks and fine tremors. She was exclusively breastfed till 4 mo of age. The mother was strictly vegetarian. On examination the infant was lethargic. Her weight was at 50th centile, length at 90th centile and head circumfer- ence at 25th centile. The developmental age had regressed to 4 wk with a Developmental Quotient (DQ) of 20. Her hemoglobin was 10.4 g/dl, ammonia 77.3 mg/dl and arterial lactate 25 mg/dl. MRI Brain (Fig. 1) revealed hyper-intense signal on T2 and hypo-intense signal on T1 in extra axial collection in bilateral fronto-temporal regions with thin subdural hemorrhagic component in the outer aspect of the collection with enlarged ventricles. A possibility of Glutaric aciduria I was kept. Tandem Mass Spectroscopy showed a normal level of propionylcarnitine. Urine GCMS for organic acids showed a 111.1 fold elevation in Methyl Malonic acid (MMA) level (1162.41 mmol/mol of creatinine). Intravenous cobalamin supplements were initiated. She had no repeat seizure and had regained her milestones within 4 wk. MMA level re- duced to 128.18 mmol/mol. However mutation analysis for mother and baby showed no pathogenic variation in any of the genes for known inherited metabolic disorders. The fa- ther carried 2 variants of unknown significance in the PAH and CPS1 gene. The diagnosis was revisited and a possibility of Infantile Cobalamin deficiency was kept. Analysis of the mother ’ s parameters revealed deficiency of Vitamin B12 137 pg/ml (211–911 pg/ml), elevated MMA in urine (310.43 mmol/ mol of creatinine).We confirmed the diagnosis of Infantile Cobalamin deficiency. The reason for referral in this case had been the MRI pic- ture. Atrophy is not commonly seen in cases of Infantile Cobalamin deficiency. To the best of our knowledge, only five cases have been reported in literature with brain atrophy in affected children [2–5]. Two of them documented normalization of the neuroimag- ing abnormalities after 10 wk of instituting therapy with co- balamin [2, 5]. However this was not seen in this case. Efforts should be directed therefore to preventing deficien- cy in pregnant and breast feeding women on vegan diets and their infants. Urinary screening for methylmalonic aciduria may be useful in this selected population to detect affected individuals. The complete reversal of symptoms is rewarding for both the parents and the clinician. * Seema Kapoor drseemakapoor@gmail.com 1 Department of Pediatrics, Lok Nayak Hospital and Maulana Azad Medical College, New Delhi 110002, India 2 Division of Genetics, Department of Pediatrics, Lok Nayak Hospital and Maulana Azad Medical College, New Delhi, India Indian J Pediatr (July 2018) 85(7):565–566 https://doi.org/10.1007/s12098-017-2542-7