Genetic metabolic disorder shows up later in life

[Monique]

It is interesting to note how a metabolic disorder can remain unnoticed in a child until some crisis occurs.

I had a case study yesterday (taking from an episode of ER) where a young child (maybe 4) gets rushed to the hospital, comatoze, seizing for 20 minutes. The child was fine that morning, just had a sore throat and thus didn't eat breakfast.

Turns out that the blood glucose is very low and is not stabilizing (very very unusual, humans have a very well attenuated glucose regulation system and someone should never become hypo).

We went over all kinds of probable diagnoses, brain infection, epileptic attack, electrolyte imbalance, poisoning, diabetes, etc. The most troubling thing is the low glucose, that just should not happen, not even with someone who has been seizing (and thus using lots of energy) for the past 20 min.

So finally we get to the conclusion that the child must have a genetic disorder in the fatty-acid metabolism. That is why the child was able to live a healthy 4 years, we normally don't use fatty-acid metabolism unless after a +-10 hour diet period.

The child for the first time in its life didn't eat breakfast, glucose levels drop and there is no fuel to generate new glucose (after using the glucose storage in the liver) so the body tries to switch to other means of energy production.

Since the child was deficient in one of the enzymes of fatty-acid metabolism, it is unable to synthesize ketones (emergency brain food) and thus the brain are depleted from nutrition and starts seizing.

The moral of the story, the ordeal of such a situation can be prevented by giving a child sugar water.

Due to the acute nature of the disease and probably misunderstanding of the symptoms, quite a high percentage of children will actually die upon presenting symptoms. The good thing is that they have started (are working on it) genetic screening within the first week after birth. Parents can be educated about the condition and be told not to let their child fast :)

 

[Ygggdrasil]

A similar genetic disorder that won't necessarily manifest itself until specific circumstances is phenylketonuria (PKU). Because PKU involves defects in metabolism of the amino acid phenylalanine, symptoms will not show up unless the individual with PKU consumes with sufficient amounts of phenylalanine. Symptoms can be avoided by tailoring the patient's diet to be low in phenylalanine, so this is another case where genetic screening of newborns is important.