Medically Reviewed by Dr. Tanmaya Metgud, Paediatrics
Written by KIE Editorial Contributors
3.5 min read | Published On: 11-10-2025
Inborn errors of metabolism are rare diseases people usually have from birth. These diseases happen when the body cannot change food into energy the right way. The main problem is that certain body chemicals, called enzymes, are missing or not working. When this happens, harmful substances can build up, or the body may not make what it needs. This can cause health problems that may be serious.
These problems can start just after birth or appear later in life. Some symptoms are mild, but others can be dangerous. There are over 1,000 types of these diseases. Each type affects a different body process. In every case, the body’s normal way of working is changed.
Signs depend on what type of enzyme is missing. Many babies look well at first but can get sick soon after birth. Some problems appear only weeks or months later.
Common signs include:
Some diseases have special signs. For example, maple syrup urine disease causes urine to smell sweet, like syrup. Noticing these signs early and getting help fast is important.
These diseases are usually grouped by what type of food the body cannot use.
These affect how the body uses sugars and starch. The body cannot get energy from sugar and may get too much waste in the blood.
Examples:
Children with these may feel weak, have big livers, or not grow well.
Protein metabolism problems stop the body from using amino acids well. When these build up, they can harm the brain.
Examples:
If not treated, these can cause slow learning or seizures. Eating special foods can help.
These affect how the body uses or stores fat. Too much fat can hurt the liver, spleen, or brain.
Examples:
Many of these get worse with time and need long-term care.
A change in a single gene causes these diseases. The gene problem is usually inherited from both parents. Parents carry the gene but may not have the disease.
Risks are higher if:
It is not caused by anything a parent does during pregnancy.
Finding these diseases can be tricky because they look like other illnesses. Special tests are needed:
Finding the problem early helps doctors start the right care quickly.
Doctors treat these diseases by managing symptoms and stopping harmful build-up. Keeping children growing and healthy is key.
Ways to treat include:
With the right plans, many people do well. New treatments, like enzyme and gene therapies, are also giving hope.
See a doctor at once if a baby has constant vomiting, seizures, or acts very sleepy. In older children and adults, warning signs are slow growth, tiredness, or getting sick after fasting. People with a family history of these diseases should see a genetic counselor before having a baby. Early tests mean early treatment, which can save lives.
How well someone does depends on the disease, when doctors start treatment, and how well the plan works. With modern care and newborn testing, many children can reach adulthood and have normal lives. Some will always need a special diet or medicine. Regular doctor visits and strict care routines are important.
These diseases are inherited, so parents with family history should see a genetics expert before planning a pregnancy. Prenatal tests and newborn screening help find these diseases before or just after birth. Raising awareness where these problems are more common also helps protect children.
Get in Touch with a Doctor
Most cases are identified through newborn screening tests, which use a few drops of blood from the baby’s heel. These tests can detect many metabolic disorders before symptoms appear, allowing treatment to start early and prevent serious complications.
Yes, with early diagnosis, proper diet, and regular medical monitoring, many children with metabolic disorders grow and develop normally. Following treatment plans strictly and maintaining regular follow-ups with specialists is key to living a healthy life.
Some metabolic disorders can impact the brain and nervous system due to toxic substance buildup or lack of essential nutrients. Early treatment and careful metabolic control help protect brain function and reduce the risk of developmental delays.
Not exactly. Inborn errors of metabolism specifically affect biochemical pathways that process nutrients, while genetic syndromes can involve a wider range of physical, developmental, or structural abnormalities caused by chromosomal or gene mutations.
While these disorders can’t be completely prevented, genetic counseling and carrier screening before pregnancy can identify if parents carry defective genes. Couples at risk can explore prenatal testing or assisted reproductive options to lower the chance of passing the disorder to their child.
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