(1) A healthy person who has one normal and one altered form of the same gene - called a heterozygote.
It may be possible to offer testing for carrier status to other members of the family when DNA tests have identified a change in a gene responsible for the condition.
(2) An individual with a structural rearrangement of the chromosomes, causing no effect on their own health or lifespan (called a balanced translocation carrier), but increasing the risk of infertility, miscarriages, stillbirths and children with multiple congenital malformations, growth retardation & learning disabilities.
It is possible to test for carrier status of chromosomal rearrangements through a cytogenetics laboratory.
