Final answer:
1) Cis deletion. Cis deletion is the type of gene deletion associated with an increased risk of severe thalassemia in offspring.
Step-by-step explanation:
The type of gene deletion associated with an increased risk of severe thalassemia in offspring is cis deletion. In cis deletion, both copies of the gene are deleted on the same chromosome, which results in a loss of function for that gene. This can lead to severe thalassemia, a genetic disorder characterized by decreased synthesis rate of one of the polypeptide chains of the globin molecule.