Metabolic disorders caused by genetic mutations resulting in enzyme
deficiencies in an intermediary metabolic pathway constitute a wide
spectrum of diseases in clinical practice. The term 'inborn errors of
metabolism' was introduced by Sir Archibald Garrod at the beginning of
the twentieth century.
Since then, a great variety of hereditary metabolic disorders have been
identified, and there has been a phenomenal increase in the knowledge
regarding these disorders.
Although individually rare, they are collectively numerous. Their
number, complexity and varied clinical presentation present a
formidable challenge to the clinician. Yet, in many cases, prevention
of death or permanent neurological sequele in patients with these
disorders is dependent on early diagnosis and institution of
appropriate therapy. In addition to comprehensive clinical assessment,
imaging studies, electrophysiological investigations and
histopathological information from biopsies, which help in establishing
the distribution and type of abnormality, biochemical studies are
required in many cases to confirm the diagnosis.
of the inherited metabolic disorders are characterized by the central
nervous system involvement and neurological symptoms are the presenting
and the most prominent clinical problems associated with them. Among
the neurometabolic disorders, there are particularly five common
neurological presentations: chronic encephalopathy, acute
encephalopathy, movement disorder, myopathy and psychiatric or