There are over 1,300 congenital metabolic diseases in which abnormal chemical reactions disrupt the metabolism. Most of these diseases are the result of a mutation in genes coding for enzymes. These diseases are inherited and usually present themselves in the presence of two recessive genes. Newborn screening is a useful aid in the early detection and diagnosis of many of these conditions.
Definition
Congenital metabolic diseases are also known as inborn errors of metabolism. Metabolism is the process in which the body uses the food we consume to harness or make energy. In metabolic diseases, there are abnormalities in the synthesis or catabolism of carbohydrates, proteins, fats and other complex molecules. These diseases involve changes in the genes that code for enzymes, which, in turn, affect metabolic pathways, resulting in toxic accumulations and defects in the production of energy.
Features
Almost all metabolic diseases have several variations that affect the age of onset, the severity of the disease and also the state in which the disease is inherited. Symptoms of metabolic diseases usually present themselves in neonates or during infancy, but, in some cases, symptoms present themselves in adulthood.
They vary in severity, whereby the most serious diseases can be fatal if not treated immediately after birth. Other adverse affects include poor growth, muscle weakness, deafness, blindness, diabetes, dental abnormalities, congenital malformations or renal failure.
Inherited
Congenital metabolic diseases are inherited. If either you, your partner or someone in your families has a , it's a good idea to undergo genetic screening and seek advice from a genetic counselor. The diseases can be categorized according to the way in which they are inherited. They can be either autosomal recessive diseases or x-linked recessive diseases.
The probability of inheriting a metabolic disease depends on the genetic makeup of both parents. For an autosomal recessive disorder to prevail, the child would need to inherit two recessive genes, one from each parent.
Types
Some of the major classes of inborn errors of metabolism are carbohydrate metabolism disorders, disorders of fatty acid oxidation, amino , organic acid disorders, urea cycle disorders, mitochondrial disorders and lysosomal and peroxisomal storage disorders.
Newborn Screening
Early detection and intervention of congenital metabolic disease can make all the difference in the health and quality of life of the child and prevent some of the physical and mental problems associated with the disease. Most states in the U.S. have mandatory newborn screening tests. Your baby's heel will be pricked 24 hours , and a blood sample taken and sent for analysis. Although the diseases screened for vary by state, most state hospitals screen for around 30 metabolic disorders. Disorders typically screened for include PKU, galactosemia, congenital hypothyroidism, sickle cell disease, maple syrup urine disease and cystic fibrosis amongst others.
Tags: metabolic diseases, metabolic disease, present themselves, acid disorders, after birth, autosomal recessive