Metabolic Evaluation in Children aged 3 months to 2 years with Global Developmental Delay

Objectives: To study the clinical profile and role of metabolic evaluation in children aged 3 mo to 2 y with global developmental delay (GDD) of unclear etiology. Methods: In this prospective study, demographic and clinical data along with first line metabolic test results [blood glucose, arterial blood sample analysis, renal function tests, uric acid, serum electrolytes, liver function tests (LFTs), plasma ammonia, arterial blood lactate and pyruvate, urine ketone/ reducing substances] were documented and analyzed. Tandem Mass Spectroscopy (TMS) and Gas Chromatography and Mass Spectrometry (GC-MS) data were also analysed. Results: Of 101 eligible children, 48 were excluded. Among 53 children included in the study, 32 (60.3%) were less than 1 y and 21 (39.7%) were more than 1 y. Four major developmental domains were almost equally affected in 16 (30.1%), three domains in 4 (7.5%) and two domains in 33 (62.4%) children. Fourteen (26.4%) children were found to have a probable metabolic disorder based on initial tests- 10 mitochondrial disorders, 3 organic-acidemias and 1 fatty-acid-oxidation defect. Further, on TMS and GC-MS tests, 11 (20.7%) had a metabolic disorder- 7 mitochondriopathies, 2 methylmalonic-aciduria, 1 each with glutaric-acidemia and ethylmalonic-aciduria. Conclusions: Among children with GDD of unclear etiology, metabolic errors constitute a small proportion of etiology. In this group early metabolic tests could identify potentially treatable conditions.