Australasian Science: Australia's authority on science since 1938

Island’s Headache May Bring Migraine Relief

By Stephen Luntz

Norfolk Island provides genetic clues to migraine susceptibility.

Norfolk Island may seem like a subtropical paradise, but for many there life is marred by pain. More than one-quarter of the population suffers from migraines, double the rate in the wider population. A study of the causes may lead to widespread relief.

“This population was used due to its unusual pedigree structure in which genetic relationships can be traced through genealogical data to the Island’s original founders, and also the high incidence of migraine sufferers in this population. It’s very useful for gene mapping purposes because of the reduced genetic and environmental diversity,” says Prof Lyn Griffiths of the Griffith Health Institute.

Griffiths has recently made a series of advances in identifying some of the genes that determine migraine susceptibility (AS, March 2010, pp. 29–31; AS, December 2010, p.11) as well as finding evidence for the soothing effects of native lemongrass (AS, May 2010, p.9). She says that, apart from the high genetic commonality, the fact that the islanders have similar diets and exposure to factors such as low pollution levels allowed the researchers to “cut down environmental issues and concentrate on the genetics”.

The study of 300 people, one-eighth of the Island’s population, found evidence for the involvement of two X chromosome genes in the Island’s migraines. Unusually for X chromosome mutations, the migraine-associated versions appear to be dominant, which Griffiths says “may explain why so many more females suffer from the disorder”.

Griffiths says that one of the genes implicated in the painful condition is involved in iron regulation in the brain, but adds: “We’re still not sure. It could be the gene next to this one.”

Griffiths has previously divided migraine-susceptibility genes into three classes: vascular, hormone-related and neurotransmitter. “I don’t know which class this is in, but it’s not hormonal,” she says.

At this stage Griffiths doesn’t know how the gene malfunctions to trigger migraines, let alone how treatment might occur. Also unknown is what proportion of migraine sufferers in the wider community have the defective genes, but Griffiths says: “We also did a study of American women with migraines and found similar X chromosomal results, so it is not unique to Norfolk Island.”