CHILDREN born to older fathers have a higher risk of eventually developing
Alzheimer鈥檚 disease, according to a new retrospective study.
Older mothers are more likely to give birth to babies with Down鈥檚 syndrome,
and people with Down鈥檚 develop Alzheimer鈥檚 disease earlier and more often than
others. Intrigued by the association between these diseases, Lars Bertram of the
Technical University of Munich and his colleagues wondered if parental age also
plays a more direct role in Alzheimer鈥檚.
The researchers studied 206 patients with Alzheimer鈥檚 disease. Susceptibility
to the disease is associated with certain major genes, so their first step was
to try to establish each person鈥檚 inherited risk. To do this they found out the
incidence of Alzheimer鈥檚 in each patient鈥檚 family.
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Then they looked at the groups of patients at each extreme鈥攃omparing
those least likely to have the disease genes with those most likely to have
them鈥攈oping to find an extra risk factor among the first group to explain
why they had Alzheimer鈥檚.
Those patients who were least likely to have inherited a major disease gene
had fathers who were significantly older than fathers of the second group and
fathers of people of the same age who did not have Alzheimer鈥檚, the researchers
report in the current issue of the journal Neurogenetics (vol 1, p
277).
Fathers of this low-probability group had been on average 35.7 years old when
their child was born, whereas the fathers of patients who were most likely to
have a major disease gene had only been 31.3 years old at the birth of their
child.
As people age, researchers suspect, damage builds up in their DNA and gets
passed on to the child. 鈥淭here鈥檚 an accumulation of environmental factors which
somehow alter the genome of the father,鈥� says Bertram.
鈥淭heir finding is extremely interesting,鈥漵ays Simon Lovestone, an Alzheimer鈥檚
disease specialist at the Institute of Psychiatry in London.