This story starts in the Sixties when doctors, mostly from Prince Henry Hospital in Sydney, made trips to remote Groote Eylandt in the Northern Territory to study the indigenous inhabitants. One of them was psychiatrist John Cawte, whose involvement with aboriginals went back to his upbringing in South Australia. Cawte had the rare honour of being inducted into an Aboriginal tribe and his studies made him a pioneer of ethnopsychiatry. Another was Lesley Kiloh, professor of psychiatry, who started off as a neurologist and already had his name on an illness – the Kiloh-Nevin Syndrome.
The doctors had their attention drawn to a bizarre illness that affected the locals. It produced a teetering gait, wasted limbs and body stiffness, leading to the term “bird people” amongst the tribesmen, who saw a resemblance to herons and the like. It was a virulent form of ataxia, its origin and intensity inexplicable. In their paper, they described thirteen, possibly sixteen, cases of neurological disorder in a group of 1100 tribal Aborigines living at Angurugu on Groote Eylandt and Yirrkala on north-eastern Arnhem Land. Sufferers were taken down to Prince Henry Hospital for tests but nothing showed up. Treatment was nugatory. Drugs provided some control of symptoms, like shaking, but the relentless progression to death continued.
What was called the Groote Eylandt Syndrome had been known to the Aboriginal people in Northern Australia for at least four generations. One possible cause was manganese poisoning arising from the BHP mine on the island (locally called Blue Mud Bay). Manganese, Cawte pointed out, was underestimated as a toxic agent – he thought it was as bad as lead. Tests turned out negative and BHP threatened to sue, so the matter was dropped. He learned from Professor Patrick McLeod, a medical geneticist at Queen’s University, Canada, that a similar rare hereditary neurological disease had been described among the Portuguese.
Further investigations followed. Epidemiologists and geneticists came in to assist. Victims of the disease were found on Groote Eylandt, Bickerton Island, Yirrkala, Elcho Island, Darwin, Ngukurr, Birany Birany, Numbulwar, Papunya, Hermannsburg, Santa Teresa (near Alice Springs) and Gunbalanya.
It took until 1995 before the answer was found. The Groote Islanders had Machado-Joseph Disease (also known as Spinocerebellar Ataxia Type 3 or SCA3), a rare hereditary ataxia. Most MJD victims are wheelchair-bound and dependent for activities of daily living within 10-15 years of symptoms arising. Unusually for a neurological disorder, it is named after patients, not doctors. The condition was thought to have originated in Sephardic Jews from north-eastern-central Portugal during the Middle Ages. Machado and Joseph were two American descendants of Portuguese families from the Azores islands of Flores and São Miguel who had the condition. Some of them emigrated to the Azores and Holland; Portuguese and Dutch colonists spread the disease widely with European international trade.
The genes that carry the mutation are nasty little numbers affecting manufacture of nerve protein of the cerebellum, hence the loss of balance, mobility and shaking. It has the same virulence – the right word for it – of Huntington’s chorea; that is, one in two descendants of a sufferer will get the condition. In addition the “anticipation effect” means that symptoms of the disease in each succeeding generation appear 8-10 years earlier and are more severe.
In China, Brazil and Portugal the illness is very rare, so why was there an upsurge in cases on Groote Eylandt? As studies of other genetic diseases show, isolation of the community has the effect of concentrating the prevalence of the gene among the local population. The result is world’s highest known incidence of MJD in indigenous people of Groote Eylandt and Yirrkala in the Northern Territory. The Machado Joseph Disease Foundation deals with about 100 people with MJD in Australia and about 650 people are at risk of inheriting the disease.
But how did the inhabitants of a remote island in the far north of Australia acquire the disorder?
For generations, traders from the Macassan islands visited the island to collect trepang (sea cucumbers). During a 200- to 300-year period up to a thousand Macassan men would camp on the Arnhem Land coast for six months a year. It was a given that they had sexual relations with the local women. It is possible that some islanders would go back with them before returning to their home. The Macassans had acquired the genes from the early Portuguese colonisation of the east, showing just what an enormous distance a mutation that started in the North Atlantic can go with the human circumstance of travel.
This story does not have an entirely bad ending. It is little consolation to those who, through no fault of their own except parentage, find they have MJD. Symptomatic treatments are improving, there is more support in the community for sufferers and at last a sense of hope that something can be done. The possible cure will come from studies into Huntington’s chorea homing in on ways to change the virulent effects of the gene, possibly with stem-cell transplants. Another approach being followed by Sydney researchers is injecting Zebra fish with the mutant gene to see how it affects the muscles and find a drug to improve it.
Illness stories do not end conveniently and nor does that of MJD. Studies in February, 2012, refined the genetics — and it turns out the source of the genes is not far-off European Portugal but Asiatic Japan, India and Taiwan. They too have their own story of trade and travel, taking their genes to the Malaccans who obligingly passed them on to the Australians. Presumably centuries ago they travelled to the Spice Islands and left their trace there. The alternate explanation is that the mutation travelled back to Portugal and then returned to Indonesia and finally the Northern Territory.
History is the warp in the woof of this story: migration, trade, sex and gene interchange – a lasting feature of the human tale. An awful lot of travel for the tiny amine blocks which cause such trouble. Not much consolation for the Bird People of Groote Eylandt. Nothing really changes.
Robert M Kaplan worked with John Cawte and Leslie Kiloh and has a lasting interest in palaeopathology for no reason that he can explain. This troubles those around him but there is nothing they can do about it