Older mothers are considerably more likely to give birth to children with tay-sachs down syndrome huntington's charcot-marie-tooth

             The correct option is down syndrome.
Reason:
            Tay sach disease is related to the abnormal function of lysosomes in which fats or lipids are deposited in brain cells, as lysosomes can not produce lipid digesting enzymes. Huntington's is a genetic disorder in which death of brain cells occurs.

down syndrome

Explanation:

Down's  syndrome is a disease that is caused due to the occurrence of an extra chromosome no. 21 and such occurrence of an extra chromosome are called as trisomy, thus trisomy 21 leads to DOwn syndrome. It is a syndrome as the disease is manifested in such a way that it affects various aspects of a person's health, such as their intelligence, facial features, physical growth, etc. The risk of having a child with Down's syndrome increases with the age of the woman, as in females all the eggs are formed at the time of birth and these eggs are the only ones that are utilized for the rest of the life for fertilization.Now, the older the eggs are the greater the possibility of improper chromosome division and hence, this could lead to the Down's syndrome in the baby.

Thus, there is a general trend that women over 35 years of age, are at a greater risk of having a child with Down's syndrome than younger women.