Transcript Achondroplasia

Achondroplasia- Dwarfism
By: Melissa Findlay
Who is most likely to get
Achondroplasia?
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Achondroplasia is an autosomal dominant condition. This means that an
achondroplasic child can be born from one of the three possible ways. The first is if
one of the parents has the disorder and the other is a big person. In this case there
is a fifty percent chance that the child will be born a little person and a fifty
percent chance that it will be born a big person.
If both parents are little people they would have also have a fifty percent chance
of having an Achondroplasic child. However they would only have a twenty five
percent chance of having a big person. The other twenty five percent would be
born homozygous dominant. These children are said to have homozygous
Achondroplasia. This condition is almost always lethal in the first year of life and
virtually all are spontaneously aborted at birth.
The last possible way of having a child with this disorder is when two big people
give birth to a little person. Seventy five percent of the little people living today
came about due to this process. This process is known as a new mutation and
occurs when the sperm is somehow develops into carrying the achondroplasic
allele. Once this happens it is just as if one of parents is carrying the gene
Continued..
• Achondroplasia is a disorder of bone growth
that causes the most common type of
dwarfism. It can be inherited as either a sex
linked trait or a autosomal dominant trait,
which means that if a child gets the defective
gene from one parent, the child will have the
disorder
Symptoms
• All people with Achondroplasia have a short stature. The average
height of an adult male with Achondroplasia is 131 centimeters
(52 inches, or 4 feet 4 inches), and the average height of an adult
female with Achondroplasia is 124 centimeters (49 inches, or 4
feet 1 inch).
• An average-size trunk.
• Short arms and legs with particularly short upper arms and
thighs.
• An enlarged head (macrocephaly) with a prominent forehead.
• Fingers are typically short. The ring finger and middle finger may
diverge, giving the hand a three-pronged (trident) appearance.
• People with Achondroplasia are generally of normal intelligence.
How common is Achondroplasia?
• Achondroplasia affects about 1 in 25,000
people.
Life threatening?
• Since two copies are fatal, if two people with
Achondroplasia dwarfism have children,
there's a 1 in 4 chance of it dying shortly after
birth
Can you be tested?
• If you have a parent with dwarfism, It is strongly
encouraged you and your short statured parent
to have a genetic consult. By testing the parent or
family member with dwarfism, they would have a
better idea of which genes you might or might
not be carrying.
• A large number of the cases of Dwarfism are also
due to random mutations with no family history.
Genes that can be passed on, but not in either
parent.
Is there treatment?
• Currently, there is no way to prevent or treat
Achondroplasia, since the majority of cases
result from unexpected new mutations.
Treatment with growth hormone does not
substantially affect the height of an individual
with Achondroplasia. Leg-lengthening
surgeries may be considered, in some very
specialized cases.
Are there support groups?
• http://www.dailystrength.org/c/Achondroplas
ia-Dwarfism/support-group
• http://www.medindia.net/patients/patientinf
o/Support_Groups/Achondroplasia.htm
• http://www.mdjunction.com/achondroplasia
Interesting facts
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Achondroplasia, which means "without cartilage formation", is a Greek word.
Achondroplasia is part of a group of disorders called chrondrodystrophies.
80% of Achondroplasia cases are caused by spontaneous mutations.
It is one of the most common of all skeletal dysplasia's
Achondroplasia is the most common type of dwarfism, affecting up to 80% of all little
people.
Most Achondroplastics are double jointed, which is caused by loose ligaments.
People with Achondroplasia usually have normal intelligence Men's average height is 51.8
inches tall which is about 4 ft. 3
Women's average height is 48.6 inches tall which is about 4 ft.
Achondroplastics seldom ever reach five feet high.
Nine out of ten children with Achondroplasia have normal sized parents.
Usually average sized kids with Achondroplastics parents are not at a higher risk of passing
the disease to their children
Absolute prevention is NOT possible
The appearance of Achondroplasia is apparent at birth.
Infants who are homozygous Achondroplasia rarely live beyond a few months
The greatest shortening occurs in the bone between the shoulder and elbow (humorous)
and the bone between the hip and knee (femur)
Bibliography
• Achondroplasia Genetic Disorder Information on
MedicineNet.com." Web. 26 Jan. 2011.
<http://www.medicinenet.com/achondroplasia/article.htm>.
• Achondroplasia." Packard Children's Hospital at Stanford
LPCH: Northern California Children's Hospital. Web. 26 Jan.
2011.
<http://www.lpch.org/diseasehealthinfo/healthlibrary/diabet
es/achondro.html>.
• Medicineplus.com. Web. 26 Jan. 2011.
<http://www.medicineplus.com/>.