Inherited Metabolic Disorders

Metabolic disorders are inherited genetic conditions that result in problems with the body’s metabolism. The condition leads to an enzyme deficiency because of a defective gene. There are more than six hundred genetic metabolic disorders, all having different symptoms. Many metabolic disorders are present in the new-born period or shortly thereafter. 

Few types of Metabolic Disorders are as under.

• Organic acidemias and amino acidopathies: This consists of a large group of disorders, which occur due to the defects in the complex biochemical pathways in the body as a result of defective function of the enzymes, cofactors or transporter protein. 

• Lysosomal storage disorders:  Lysosomal are spaces inside the cells that break down waste products of metabolism. When toxic substances build up in the cells (due to enzyme deficiency), it can cause the following disorders:
  

  • ​​​Nerve damage, also known as Krabbe disease, which causes development delays in children​​

  • Bone pain, enlarged livers and low platelet counts known as Gaucher’s Disease​​

  • Hurler Syndrome, which results in abnormal bone structure and delays in development
    

  • Tay- Sachs disease causes progressive weakness in children which leads to death in three to four days.
    

• Galactosemia: This causes jaundice, vomiting, and liver enlargement after breast or formula feeding by a new-born. It is because of the impaired breakdown of the sugar galactose. ​​

• Maple Syrup Urine Disease: This builds up amino acids in the body which results in nerve damage and the urine smells like syrup. This is caused by deficiency of an enzyme called BCKD.

• Phenylketonuria (PKU): This results in high levels of phenylalanine in the blood (which contribute to developmental delays in children). If the condition is not recognized, it can result in mental retardation. It is caused by deficiency of the enzyme PAH.

• Mitochondrial Disorders: Problems inside mitochondria (the powerhouses of cells), which comprises of a heterogeneous group of disorders, which often have multi-system involvement. Defective functions of the mitochondria leads to damages of organs, which are high energy dependents including the muscles, brain, eyes and heart. However, any organ of the body can be involved.

• ​Metal Metabolism Disorders: Levels of trace metals in the blood are controlled by special proteins in the form of enzymes and transporter proteins.​

When to seek expert advice

These disorders are usually present at birth and doctors at the Department of Paediatrics will be able to diagnose them at birth.