Australasian Science: Australia's authority on science since 1938

Autism Linked to Pink Disease

By Stephen Luntz

Children with a family history of pink disease have a higher risk of developing autism spectrum disorder, researchers at Swinburne University of Technology have claimed, but their evidence has been swiftly challenged.

Pink disease results from mercury exposure, possibly in combination with a genetic hypersensitivity. In the first half of the 20th century mercury was used in teething powders and one in 500 exposed children developed the condition, with symptoms including itchiness, muscle weakness and sensitivity to light. Substantial numbers of sufferers died from secondary bronchial infections.

In recent years there have been claims that autism results, at least in some cases, from mercury exposure. Research has been equivocal, but anti-vaccination groups have latched onto the cause even though mercury was removed from childhood vaccines a decade ago. Typical mercury dosages are not damaging to most children, but the theory’s proponents suggest that those with a particular sensitivity may be more vulnerable to autism.

A/Prof David Austin sought to test the hypothesis that if hypersensitivity to mercury contributes to autism such sensitivity would be hereditary and might show up in a family history of pink disease.

Austin located more than 500 survivors of pink disease and collected data on 1100 children and 1360 grandchildren. “We asked about the frequency of autism, but also a range of other conditions as a control for our survey methods,” Austin says.

“Staggeringly, we found that one in 25 grandchildren of pink disease survivors aged 6–12 had been diagnosed with an autism spectrum disorder. This compares to the current Australian prevalence rate for that age group of one in 160.”

No other conditions were more common among pink disease survivors than the general community.

Austin doubts that the experience of pink disease triggered changes that were passed onto descendents. Instead his explanation lies in a combination of genes creating an unusual sensitivity to mercury, which can express itself either as pink disease or autism.

No genetic test for mercury sensitivity is available. Austin notes it is not always possible to establish a family history of pink disease since the condition occurred when children were too young to remember.

“Really the advice after our research is the same as it was before. Pregnant women and breastfeeding mothers should moderate their intake of seafood and opt for non-amalgam fillings,” Austin says. However, those with a known family history of pink disease should take particular care.

The research has been published in the Journal of Toxicology and Environmental Health but it has been sharply criticised on science-orientated blogs, both for making citations to thoroughly discredited papers and for failure to control for potentially confounding factors.