Discovery offers key to children's disease

By MICHAEL OTTO

An Auckland scientist's discovery has the potential to help beat one of the world's rarest childhood disorders, Costello syndrome.

Sufferers typically fail to thrive, have coarse facial features, lax skin and develop late. Many parts of the body are affected. At least 26 cases have been reported worldwide in medical literature and as many as 150 children are believed to have the condition, the cause of which is a mystery.

Costello syndrome was first reported in 1977 by a New Zealand paediatrician, Dr Jack Costello.

In 2000, Canadian researchers discovered that victims lacked an essential binding protein used to assemble elastic fibres on the surface of cells in their bodies.

The Canadians are using Auckland scientist Associate Professor Mervyn Merrilees' 1998 discovery of how to switch on the production of elastic fibres to correct that deficiency.

Led by Dr Alek Hinek, of the Hospital for Sick Children in Toronto, the Canadians worked with Professor Tom Wight's research team at the Hope Heart Institute in Seattle to achieve this.

Professor Merrilees, of the University of Auckland School of Medicine, is excited by the development.

"I don't want to extrapolate too far, but it is a significant and quite extraordinary advance.

"In a sense the problem has been cured in a dish and that is a long way from the patient - but now the work has reached a whole new level of understanding."

The Canadian findings will be published shortly in the American Journal of Pathology.

Professor Merrilees discovered how to switch on elastin while on sabbatical leave at the University of Washington in 1998. His findings were published in Circulation Research last year.

He says not being able to assemble elastic fibres on cells creates all sorts of problems.

"Elastin is not just to provide you with stretchy tissues - which you need for your skin, lungs and arteries.

"Removal of the gene for elastin leads to unusual growth and thickening of vessels, and the airways of the lung don't branch properly."

Dr Salim Aftimos, paediatrician at the Medical Genetics Department of Auckland Hospital, thinks that one New Zealand scientist's discovery being used to improve understanding of a syndrome discovered by another New Zealander is "neat".

Since the two cases reported by Dr Costello, Dr Aftimos knows of only two other possible cases of the syndrome in New Zealand.

A distinguishing feature that aids diagnosis is the development of warty growths around the nose, he says.

Given the syndrome's rarity, there is very little literature on what happens to sufferers in adulthood.

Dr Aftimos says the children have endearing personalities.

He thinks the discovery of the shortage of elastin binding protein on Costello syndrome patients' cells helps to explain some of the symptoms such as the lax skin and cardiac anomalies including narrowing of heart valves and thickening of cardiac muscles.

However, he says some other aspects of the syndrome need further explanation, especially the developmental delay in the children.

* Michael Otto is an AUT journalism student.