Introduction Inborn errors of metabolism (IEM) comprise a large group of more than 500 different rare genetic disorders. They arise due to mutations in genes encoding a single enzyme in metabolic pathways. Some of these disorders are very rare, whereas certain other disorders are more common. There are considerable racial and ethnic differences in the incidence pattern of these disorders. Amino acidurias like phenylketonuria are common in the Western population; in Asian countries including India, organic acidurias like propionic acidurias, methyl malonic acidurias and maple syrup urine disease are more common. Clinical presentation of IEM is varied and it affects multiple organ systems, including CNS. Indeed CNS involvement is one of the most common presenting symptoms. The diseases can appear immediately after birth; or sometimes it may be delayed, even appearing in adult life. In this chapter we shall describe our experience with metabolic screening in the last 5 years. This is followed by a presentation of some important case histories along with their laboratory work-up. We then go on to discuss the current global status in diagnosis and management of these diseases. It should be emphasized at the beginning itself that our laboratory (Metabolic Disorders Laboratory, Amrita Institute of Medical Science, Kochi, Kerala, S. India) is a referral center for the state of Kerala as well as the neighboring states in South India. Hence the studied population represents children who are suspected to have IEM or are high-risk individuals, or who have been referred from other hospitals in this part of India. Hence the results described do not reflect the population incidence. If these patients are not diagnosed and treated early in life, they go on to have irreversible damage. Many body systems are affected, and the predominant damage will be to the central nervous system. The babies may develop permanent mental retardation, growth retardation, intractable seizures, cerebral palsy etc.
K. Vaidyanathan, Dr. Damodaran Vasudevan, and Narayanan, M. P., Inborn Errors of Metabolism and Brain Involvement-5 Years Experience from a Tertiary Care Center in South India. INTECH Open Access Publisher, 2012, p. 21.