What do you suggest if my grandmother and my mother both have tested positive for celiac disease. is it a dominant or recessive trait?

Genetic: you may carry the gene for celiac- It is not a dominant or recessive gene. It is a gene that is associate to a chromosome that has been identified. In order to get the condition, you need to have the gene and an environmental trigger. You can be tested to see if you have the gene. The DR8 gene profile is seen in a large part of the population and may explain why celiac is being seen often.

Neither: While you may inherit the immune risk factor from a parent that does not guarantee getting Celiac disease. If you have a 1st degree relative with confirmed Celiac disease then there is roughly a 20% chance of developing it in your lifetime. But it is more likely you will never get it!