Causes
of Hearing Loss
Glossary
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 Autosomes
- The 22 pairs of chromosomes that contain genes that do
not determine your sex. These are numbered from the largest
(#1) to the smallest (#22) pairs.
Chromosome - A collection of
many hundreds or thousands of genes strung together like
beads on a string. There is no rhyme or reason for the order
of the genes on a chromosome. Humans usually have 46 chromosomes
(23 pairs) and they are found in the nucleus of each cell
in your body (with the exception of the cells responsible
for reproduction). One pair of chromosomes determines your
sex (Sex Chromosomes); all the other chromosomes
are called Autosomes. Think of a chromosome as one
of a volume of books, each containing many sentences (genes).
Since chromosomes come in pairs, then genes also come in
pairs. This is the basis for the different types of inheritance:
Dominant and Recessive.
Dominant gene (inheritance)
- Since genes come in pairs, a dominant gene is always expressed
(message is read) regardless of the message on the other
gene.
Gene - A coded message that
tells the body how to make a chemical substance that the
body needs. For example, the gene that codes for the molecule
hemoglobin, which carries oxygen in the red blood cells,
is found in humans on chromosome #9. Think of a gene as
a sentence in a book.
Hearing Loss - The condition
of less than full hearing capacity. The degree of hearing
loss can have different terms; hard of hearing, hearing
impaired and deaf are three of the more common terms. Unless
otherwise specified, hearing loss includes all of these
sub-classifications.
Recessive gene (inheritance)
- If paired with a Dominant gene, the message of the recessive
gene will not be expressed. However, if paired with another
recessive gene, then the message will be expressed.
Sex Chromosomes - The one pair
of chromosomes that determine your sex. In humans, females
have two "X" chromosomes, while males have one
"X" and one "Y" chromosome. Therefore,
human males determine the sex of the children (whether the
sperm contains the "X" or "Y" chromosome).
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