Variants in trans: A person with two variants on separate chromosomes (in trans) will pass on one variant to each of their children. If their partner is not a carrier, each child will be a carrier for GJB2-related hearing loss.

If their partner is a carrier, each child has a 50 percent (1 in 2) chance of being a carrier and a 50 percent (1 in 2) chance of having GJB2-related hearing loss.

Variants in cis: If a person has two variants on the same chromosome (in cis), each child has a 50 percent (1 in 2) chance of inheriting both variants and a 50 percent (1 in 2) chance of inheriting no variants. If their partner is not a carrier, each child has a 50 percent (1 in 2) chance of being a carrier of GJB2-related hearing loss.

If their partner is a carrier, each child has a 25 percent (1 in 4) chance of having GJB2-related hearing loss.