The Inheritance of Retinal Degenerations

Glossary

Click for Table of Contents
autosomal dominant
a trait (or a disease) that is produced when only one copy of a gene is present


autosomal recessive
a trait (or a disease) that is produced only when two copies of a gene are present


autosome
one of the non-sex chromosomes; there are 22 pairs of autosomes


carrier
an individual with one mutated gene paired with one normal gene; a carrier of a gene for a recessive disease does not have the disease


carrier detection
using tests to determine who carries a mutated gene for a recessive disease


cell
the smallest unit of living matter; the human body is made up of about 10 trillion cells


choroid
the layer of the eye behind the retina that contains major blood vessels


chromosome
a microscopic, rod-like structure in the cell's nucleus that carries genetic material


conception
the union of an egg and a sperm that forms a cell capable of surviving and maturing, which results in pregnancy


congenital
present at birth


DNA
deoxyribonucleic acid, the molecule that holds genetic information; it is the biochemical molecule that makes chromosomes and genes


enzyme
a protein involved in an important biochemical reaction in the body; a defective enzyme can be the result of a mutated gene


family history
information about an individual's family concerning its medical background and usually concentrating on the history of disease, birth defects and reproduction


gene
a unit of heredity; composed of deoxyribonucleic acid (DNA)


gene therapy
the administration of genetic material into cells of a patient to correct or replace a specific gene that is not working properly


genetics
the science concerning genes and heredity


genetic counselor
a professional trained to evaluate a family's medical history to determine the presence of genetic diseases or other inherited traits and to assess the risk of these occurring in other family members


inheritance pattern
the way in which a gene or trait is passed through generations of a family


inherited
passed through generations of a family, from parents to children


isolated
occurring in only one individual in a family


linked
two or more markers that are close enough together on a chromosome to be inherited together


macula
the central area of the retina


marker
a gene or DNA fragment with a known location on a chromosome that is associated with a certain disease; it can be used as a point of reference when looking for disease-causing mutations


medical geneticist
a medical doctor who specializes in the diagnosis and treatment of inherited diseases


mutation
a change in a gene


myopia
nearsightedness


neurologic
concerning the nervous system


night blindness
inability to see at night or in areas with low lighting


nucleus
a structure within the cell containing genetic material


ophthalmologist
a medical doctor who specializes in the diagnosis and treatment of eye diseases


pedigree
a multigenerational family tree using symbols to denote lineage and genetic information


peripheral
side


prenatal diagnosis
the diagnosis of a disease in an unborn baby


presymptomatic diagnosis
the diagnosis of a disease before the onset of clinical symptoms


retina
the layers of cells in the back of the eye that are responsible for sensing light and transmitting light- induced signals to the brain


reduced penetrance
when the effect of a mutated gene for a dominant disease is somehow modified or reduced and does not always cause disease when present


sex chromosome
an X or Y chromosome; the Xx pair determines female and the XY pair determines male


trait
a distinguishing characteristic


unaffected
not having the disease


variable expressivity
when the effect of a mutated gene for a dominant disease may be severe in one member of the family and mild in another

[Click for Previous Page] [Go to Top of Page] [Click for First Page]



EMail
Send comments to rpmail@jwen.com

Date last modified January 23, 2000