Depression, memory lapses and fits of rage are not a direct result of any type of
DI. However, they might be an indirect result of dehydration and brain damage caused by
DI during infancy. From the other symptoms you describe, your son probably does have some form of
DI although it may be partial and less severe than most. Since he has a cousin on his father's side who has documented
pituitary DI, your son probably has the same type of
DI on a
genetic basis. If so, the
genetic mutation is unique since neither of the brothers with affected sons has
obvious signs or symptoms of
DI. I would recommend that your son be evaluated to determine if he has
pituitary DI. If he does, he should start appropriate treatment and, along with his cousin and other relatives, have a genetic analysis to try to identify or at least
localize the
mutation responsible.