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April 29, 2009

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Gene tied to lower cognitive function in kids

Nov. 5, 2007
Courtesy Oregon Health & Science University
and World Science staff

Chil­dren with a gene known to in­crease the risk of Alzheimer’s dis­ease al­ready show signs of re­duced cog­ni­tive func­tion, a study has found. That raises the pos­si­bil­ity that sci­en­tists could de­vel­op ther­a­pies to block the gene’s neg­a­tive ef­fect­s—and stave off cog­ni­tive de­cline start­ing much ear­li­er in life than pre­vi­ously thought pos­si­ble, the re­search­ers said.

The in­ves­ti­ga­tors, with Or­e­gon Health & Sci­ence Un­ivers­ity, found re­duced spa­tial learn­ing and mem­o­ry skills in chil­dren with one of a family of genes im­pli­cat­ed in de­vel­opment and in nerve cell re­genera­t­ion and pro­tec­tion. The re­sults were pre­sented Nov. 5 at the an­nu­al meet­ing of the So­ci­e­ty for Neu­ro­sci­ence in San Die­go.

Pre­vi­ous stud­ies had found that a gene known as apoE4—part of the so-called apo­lipo­pro­tein E gene family—in­creases the risk of cog­ni­tive de­cline due to age and brain in­ju­ries. Half of Alzheimer’s pa­tients car­ry apoE4, said study co-author Ja­cob Raber. Many non-demented eld­erly al­so car­ry it, he added, but they tend to do worse than oth­ers on cer­tain cog­ni­tive tests.

In the new stu­dy, Raber and col­leagues ex­am­ined 55 healthy boys and girls ages se­ven to 10, in­clud­ing eight girls and six boys who car­ried the apoE4 gene. The non-carriers showed better performance on a com­bina­t­ion of paper- and com­pu­ter-based tests, they said. These in­clud­ed a virtual-real­ity based spa­tial naviga­t­ion task called “Mem­ory Is­land” whose sub­jects must use mem­o­ry to nav­i­gate to a loca­t­ion marked with a flag. The test mim­ics the Mor­ris wa­ter maze, a stand­ard tool for test­ing mem­o­ry in ro­dents by train­ing them to swim to a plat­form based on vis­u­al cues.

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Children with a gene known to increase the risk of Alzheimer’s disease already show signs of reduced cognitive function, a study has found. That raises the possibility that scientists could develop therapies to block the gene’s negative effects—and stave off cognitive decline starting much earlier in life than previously thought possible, the researchers said. The investigators with Oregon Health & Science University’s School of Medicine found reduced spatial learning and memory skills in children with one of a family of genes implicated in development, and nerve cell regeneration and protection. The results were presented Nov. 5 at the annual meeting of the Society for Neuroscience in San Diego. Previous studies had found that a gene known as apoE4—part of the so-called apolipoprotein E gene family—increases the risk of cognitive decline due to age and brain injuries. Half of Alzheimer’s patients carry apoE4, said study co-author Jacob Raber. Many non-demented elderly also carry it, he added, but they tend to do worse on cognitive tests. In the new study, Raber and colleagues examined 55 healthy boys and girls ages 7 to 10, including eight girls and six boys who carried the apoE4 gene. The children were assessed using a combination of paper- and computer-based tests, including virtual-reality based spatial navigation test called “Memory Island” in which they must use their memory to navigate to a location marked with a flag. The test mimics the Morris water maze, a standard scientific tool for testing memory in rodents by training them to swim to a platform based on visual cues. Non-apoE4 carriers showed better spatial memory retention and searched more frequently for the targets in the appropriate quadrants, Raber and colleagues said.