Is the type of bipolar disorder constant when bipolar runs in families?

Not really: Family history increases risk of having bd, but it does not change the presentation. By definition, people with bd have ups and down, usually interspersed with periods of normal mood. The ratio or ups versus downs often changes as people age, but not predictably. Some start with mostly manic episodes, others most depressed; many teens have "mixed" episodes with features of both mood states.