BY investigating the extraordinary case of a 16-year-old girl locked perpetually in the mind and body of a baby, it may be possible to identify the master switch that controls ageing.
of the University of South Florida College of Medicine in Tampa and his team are comparing the DNA of 鈥渢een baby鈥� Brooke Greenberg, from Baltimore, Maryland, with that of her three healthy sisters, her parents and standard human DNA sequences in the human genome database. The idea is to track down the gene, or group of genes responsible for ageing.
If such a gene can be found, it may one day allow people to stay forever young as did Oscar Wilde鈥檚 character Dorian Gray.
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Despite being 16, Brooke is equivalent in size and mental development to an 11-month-old baby. But the first full scientific investigation of her case has revealed that she is not simply frozen in time. Instead, her condition has been traced to different parts of her body maturing at different rates, instead of in synchrony.
鈥淚 think she has differential growth of her body. It鈥檚 not growing as a unified organism, but in fragmented parts,鈥� says team leader Walker (Mechanisms of Ageing and Development, ).
鈥淏rooke鈥檚 body is not growing as a unified organism but in fragmented parts鈥�
Brooke鈥檚 brain is scarcely more mature than that of a newborn infant, for example, whereas her bones are as mature as those in a 10-year-old (though still small), and she still has the milk teeth of an 8-year-old. She is fed through a tube in her stomach because her respiratory and gastrointestinal systems are maturing out of sync so she can鈥檛 swallow easily or safely.
Walker thinks that Brooke is the first recorded case of what he describes as 鈥渄evelopmental disorganisation鈥�. He suspects she has mutations in a hypothetical 鈥渞egulator鈥� gene 鈥� or group of genes 鈥� thought to orchestrate development up to adulthood and reproductive age, but as it carries on working ageing is the result. 鈥淚f you could halt that in young adulthood, the effects should be stopped and we should enjoy sustained youth and vitality,鈥� says Walker.
While rejuvenation would not be possible, Walker stresses, ageing could potentially be stopped. 鈥淲hat you鈥檙e doing is arresting physiological degradation, and if it鈥檚 true that ageing is stoppable, then hypothetically we may be able to sustain life indefinitely.鈥�
Walker says that Brooke鈥檚 haphazard development is probably the closest manifestation yet of what happens when the hypothetical regulator is disrupted. Gene scans so far have shown that she has no abnormalities in genes linked to any known disorder that causes premature ageing, such as progeria or Werner鈥檚 syndrome. If the project uncovers any promising mutations the relevant genes will be transferred to mice to look for alterations in their longevity or the timing of different body phases such as reproduction.
