Answer:
If a person has asthma which can be triggered by cats it is best not to get one for them at all.
Siberian cats and some others produce lower levels of Fel d1, the protein in the cats' saliva that allergic people are really allergic to. Some people will still have an allergic reaction, depending on how bad their allergies are and the level of Fel d1 in the particular individual cat. If you really want to get a cat for a person with allergies, find a Siberian cat breeder and get a Siberian. You can use small fur samples from the cats from the breeder to see which one doesn't cause an allergic reaction, then get the cat to which the fur belongs to. Good luck. :)