Introduction: Neuro-metabolic disorders are a common cause of developmental delay/regression but are difficult to diagnose in most cases. High index of suspicion should be kept if no cause of developmental delay or regression can be found.

Methods: Clinical evaluation followed by neuroimaging and tandem mass spectrometry in the patients

Case Description: A family of third degree consanguineously married couple presented with their three children, 5 year old boy, and two girls aged 3 years and 9 months. The eldest sibling had regression of milestones while the second born child had a global developmental delay. The youngest sibling was developmentally appropriate at presentation. On examination, all had microcephaly, spasticity and brisk reflexes. The magnetic resonance images of brain were normal for the two elder siblings.

Results: Plasma ammonia levels were mildly elevated. Tandem mass spectrometry revealed elevated levels of arginine consistent with argininemia.

Discussion: Argininemia is a urea cycle disorder which has a myriad of presentations. A high index of suspicion is required to diagnose neuro-metabolic disorders. We hereby discuss clinical presentation of a child with the said condition.

Acknowledgements: We thank the patient and his family for their cooperation