When fats are burned for energy, they are shortened in cycles, starting out as so-called long chains, which are then systematically broken down to medium and finally to short chains. Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is a genetically inherited condition in which individuals lack the molecular tools – called enzymes – to effectively break down medium chains. This can be especially dangerous in children.
That said, different children can often have very different outcomes – some becoming severely ill while others do not even notice that they have it. While we know that our bodies can adapt by repurposing the enzymes usually dedicated to long and short chains, these substitutes are less efficient at breaking down medium chains. This slows down fat burning and causes medium-chain fats to accumulate to toxic levels. Various mechanisms exist by which these effects can be counteracted, including producing additional enzymes that can burn fats faster and disposing of the accumulated toxic molecules before they are fully broken down. Each of these responses incurs a cost, however, and often multiple small responses happen simultaneously. A combination of responses is often difficult to understand. This is helped by the use of computer models which can calculate the sum of small changes. If we could know how each individual adapts, we might be able to predict who is at risk and who not, so doctors can act with greater precision. Johannes Odendaal built such a computer model and identified some molecular changes linked to decreased risk in children with MCADD.
