MCADD is the shortened name for Medium Chain acyl CoA Dehydrogenase Deficiency. It is a rare inherited condition which is caused by the body’s inability to break down (metabolise) fat properly due to a lack of an enzyme. MCADD belongs to a group of disorders known as the Fatty Acid Oxidation Disorders (FOD’s). Our bodies mainly store energy in the fat or adipose tissue. This comes from the fat that we eat and can also be made in the body from excess calories that we consume. When fat is broken down it releases fatty acids which are a major energy source especially when we have not eaten for a number of hours. In MCADD these fats are not completely broken down and this leads to an accumulation of medium-chain fats in the body. If the body needs to break fats down quickly, such as after a long period without food or during an illness, the build up of medium chain fats can produce toxic substances that lead to severe symptoms including seizures and possibly coma.
People with MCADD have to rely on glucose for their energy and during an illness or long periods without food their glucose supplies may be low. This leads to dangerously low blood sugar levels and a build up of toxins in the body and can be life threatening. Thankfully, with early diagnosis and with the help of a specialist medical team, MCADD can be quite easy to manage and those affected by this condition have a good prognosis.
Symptoms of this disorder tend to appear between 3 to 18 months of age, although some cases do present soon after birth & occasionally in older infants and exceptionally in adults after prolonged fasting/ metabolic stress. Symptoms generally occur as recurrent episodes of metabolic crisis, which are often triggered by an infection, and/or a period of fasting. These metabolic crises tend to vary from case to case both in symptoms and severity. Sudden severe, life-threatening symptoms can occur at any time for those undiagnosed causing coma and/or death if not treated quickly, although acute problems are rare in children older than 5 years.
· Low blood sugar levels (hypoglycaemia) usually with a reduction in the amount of ketones (hypoketotic hypoglycaemia).
· Increased level of acid in the blood and the body (metabolic acidosis)
· Breathing difficulties (respiratory distress)
· Liver disease with an enlarged liver (hepatomegaly)
· Drowsiness
· Fits
· Coma
Individuals with MCAD deficiency can develop high levels of ammonia in the blood (hyperammonemia), leading to fluid accumulation around the brain (cerebral oedema). This disorder can in some children lead to delays in mental and physical development.
Current Recommendations in the UK:
0-4 months 6 hours
4-8 months 8 hours
8-12 months 10 hours
12+ months 12 hours
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