Mutation that causes MCAD deficiency
A gene mutation is a permanent change in the
DNA sequence that makes up a gene.
gene holds the instructions or "recipe" to create a protein. By
changing the gene's instruction for making that protein, the protein
can be malfunctioning or even completely absent.
Different kinds of
mutations are possible, for example:
- a change in one DNA base
pair, replacing for example a G with
- adding a piece
- removing a
piece of DNA
- duplicating a
piece of DNA
of a change in one DNA base pair:
The mutation that causes MCAD deficiency is a mutation on the ACADM
most classic mutation of this gene is called "A985G", and is of the type where one DNA base pair is
changed: an adenine (A) is replaced by a guanine (G) at
But tens of other mutations of this gene are
known that cause MCAD deficiency.
The "address" of the ACADM
gene is 1p31.
Geneticists use a
standardized way to describe a gene's location.
chromosome looks a bit like an X, but the place where the 2 lines
(called arms) cross is not exactly in the middle. So one arm is shorter
than the other.
By convention the short arm is called the p arm. The long arm is called
the q arm.
The position of a gene is based on a distinctive pattern of dark and
light bands that appear when the chromosome
is stained in a certain way.
Positions are defined on a chromosome using these bands. Positions are
indicated by numbers.
write down the address of the gene, geneticists write the number of the
chromosome, followed by a p or q, and then the position.
address of the ACADM gene is 1p31, that means that it is located on the
first chromosome, on the short arm and on position 31.
That explains the image on top of this site :-)
Gene mutations for the ACADM gene
occur in two ways: they can be
inherited from the parents or they can be newly created in the egg or
sperm cell the baby originates from. In both cases the mutation is
present at conception and the baby will be able to pass it on to his or
further about how this mutation is inherited >