Dec. 3, 2006 — I recently read that
schizophrenia is related to the age of the father. Is
this condition mitotic in origin?
—Submitted by Virginia Ghattas, high school biology
teacher in Massachusetts
Response
by Andreas Hochwagen
Whitehead Fellow
You are right, the risk of developing schizophrenia
does indeed correlate with the age of the father. Children
of fathers 50 or older have about a 5 times higher risk
of developing schizophrenia compared to children of
fathers aged 21 to 24.
Unfortunately, basically nothing is known about the
origin of this age dependence. Schizophrenia is a very
complex disease that is difficult to diagnose (at present
doctors use a list of seven criteria, any five of which
are sufficient to diagnose a patient with schizophrenia).
It is very likely that a number of different genetic
and environmental influences are responsible for this
disorder. Probably because of this complexity, no reliable
genetic risk factors have been identified thus far.
Seeing that the risk increases in children with older
fathers has led researchers to suggest that the sperm
producing cells accumulated mutations over time. Alternatively
the regulatory structures on chromosomes (so-called
epigenetic regulation) may have deteriorated over time
in older fathers. This defect could then be passed on
to the offspring. However, none of these theories have
been proven at this point.
