Inborn Errors of Metabolism (IEM) are rare 
congenital diseases. It arises due to a defect of single genes 
that code for enzymes that helps to convert substrates into 
their products by participating in certain metabolic pathway. 
IEM affects every organ, from the fetus to geriatric life. 
Majority of IEM are inherited in an autosomal recessive 
manner. The frequency for each individual disease is decided 
by the geographical and ethnic composition of the 
population. The incidence of IEM varies from community to 
ethnicity to religion to location. Any patient with 
unexplained neurological condition should be considered for 
an underlying IEM. Newer scientific technologies have to be 
converted into diagnostic and therapeutic use which can offer 
enormous benefit to patients suffering from IEM, and 
preventing life-long burden and suffering. The overall aim 
should be to diagnose IEM early in life in order to prevent 
neurological damage and loss of life.