Each year a number of children are born with biological defects that impair normal function. For THREE of the following conditions, discuss such aspects as the biological cause, the methods of treatment and possible means of detection and/or prevention. One lethal disorder inherited as a recessive allele is Tay-Sachs disease. This is caused by a dysfunctional enzyme that fails to break down brain lipids of a certain class. The symptoms usually become manifest a few months after birth. Some symptoms are seizures, blindness and degeneration of motor and mental performance. Death is the result of this disease, in children. With...
age, the hypothesis that older women are more likely than younger women to carry Down babies to term rather than spontaneously aborting the trisomic embryos.

One way to detect this is to use an amniocentesis, which can determine whether a developing fetus has these diseases. Tests for disorders are performed on cells grown in the laboratory from the fetal cells that had been sloughed off into the amniotic fluid. In an alternative technique called chorionic villus sampling, the physician suctions off a small amount of fetal tissue from the placenta. These results can be found quicker, within 24 hours.