Birth Defect Terms and Definitions

Codominance
Situation in which two different alleles for a genetic trait are both expressed.

Haploid
A single set of chromosomes (half the full set of genetic material) present in the egg and sperm cells of animals and in the egg and pollen cells of plants

Centromere
A specialized chromosome region to which spindle fibers attach during cell division.

Amino acid
Any of a class of 20 molecules that are combined to form proteins in living things.

Pedigree
A family tree diagram that shows how a particular genetic trait or disease has been inherited.

Birth defect
Any harmful trait, physical or biochemical, present at birth, whether a result of a genetic mutation or some other nongenetic factor.

Mutation
Any heritable change in DNA sequence.

Risk communication
In genetics, a process in which a genetic counselor or other medical professional interprets genetic test results and advises patients of the consequences for them and their offspring.

Syndrome
The group or recognizable pattern of symptoms or abnormalities that indicate a particular trait or disease.

Embryonic stem (ES) cells
An embryonic cell that can replicate indefinitely, transform into other types of cells, and serve as a continuous source of new cells.