Tuesday, 26 April 2011

Jaundice, bilirubin and autism

Jaundice is a common problem for the neonate. It is common because the figures suggest that anywhere up to 50% of newborns may present with jaundice during earliest infancy and even more frequently in those babies born slightly preterm.

The primary overt symptom of jaundice is the characteristic yellowing of the skin starting with the face and progressing throughout other areas of the body. The primary clinical correlate to this symptom is the increase in levels of bilirubin - a metabolite of heme.

Why is jaundice an important observation to the newborn? Well basically because bilirubin is toxic and has the ability to do some pretty terrible damage to the newborn; the end-point potentially being kernicterus (bilirubin encephalopathy).

OK so what is the connection to autism? Is there a connection?

Well this very much depends upon how you look at the research. I can remember many years ago talking to Dr Rosemary Waring, famed for the sulphate research in autism about bilirubin and its cousin, biliverdin. Rosemary (and a few others including Paul Shattock) had some interesting ideas about the effects of low sulphate levels on the metabolism/breakdown of bilirubin and biliverdin. These ideas still remain today albeit stagnant in research terms.

The more direct work on jaundice in autism is interesting. This paper suggested that various bilirubin levels might show some association with ADHD and developmental delays (to include autism). This paper said pretty much the same thing with specific regards to autism. One might get the impression that something was brewing with regards to a possible relationship between autism and hyperbilirubinaemia.

Well not so fast. There is some evidence to suggest that any relationship is not going to be so clear-cut. Indeed certain questions have been raised about research suggesting a link between jaundice and autism (and other issues of psychological development).

Where to go from here?

There may be yet more we can learn from examining any relationship between autism and jaundice / bilirubin. The fact that several 'conditions' have been linked to jaundice / bilirubin is still an intriguing finding and perhaps opens up avenues towards a more generalised relationship.