Download Genetic Disorders - Learn District 196

A genetic disorder is a condition caused by
abnormalities in genes or chromosomes.
Most disorders are rare and affect 1 in hundreds
of thousands or millions
A genetic disorder is not always detrimental
Alibinsm
 Symptoms
 Absence of color in the hair, skin, or iris of the eye
 Lighter than normal skin and hair
 Patchy, missing skin color
 Cause: Inheritance of 2 mutated genes (rare)
 In animals, survival of albinos is challenging
Dwarfism
 Most forms of dwarfism have a genetic basis. Most cases
(75-90%) of achondroplasia, however, are the result of
sudden mutations of a chromosome.
 For this reason, most achondroplastic dwarves are born to
normal parents.
 There is a 25% chance that two achondroplastic dwarves
would give birth to a normal child, and it is also possible
for two achondroplastic dwarves to conceive a doubledominant child, where both parents pass on the gene for
achondroplasia. This condition is fatal, and results in a
miscarriage or a very short lifetime for the child.
Down’s Syndrome
 Triosomy-21 (Extra chromosome 21)
 Affects about 1 in 800 babies per year is the US
 Related health problems (heart, digestive system,
intellectual disabilities)
 May have shortened life due to health issues
Hemophilia
 Blood does not clot normally (coagulation)
 A sex linked recessive disorder
 More common in males than females
 Female is more likely to be a carrier
Polydactyly
 Extra digits (fingers or toes)
 Caused by a genetic mutation
 Not uncommon in cats
Klinefelter’s Syndrome
 XXY Genotype (XY is normal)
 Due to nondisjunction during meiosis
 Individual is most likely infertile
 Affects about 1 in 1000 males
XXX Syndrome
 Trisomy X Syndrome is due to nondisjunction during
meiosis
 Results in extra chromosome
 Affects about 1 in 1000 females
 No readily observable abnormalities
Sickle Cell
 Blood cells are shaped like crescents instead of round
 This causes problems with circulation and the bloods
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

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ability to carry oxygen
Recessive gene.
Parent may be a carrier for sickle cell (have the trait
but not the disease)
May have life long pain, fatigue.
No cure at this time
Sickle Cell
Marfan Syndrome
 Unusually tall (legs, arms, fingers)
 Dominant Trait
 May affect cardiovascular system, (heart & lungs) and
central nervous system
Colorblindness
 Most color blindness is due to a genetic problem.
 About 1 in 10 men have some form of color blindness.
 Very few women are color blind.
Lactose intolerance (Galactosemia)
 Disorder due to a genetic mutation
 Individual unable to produce lactase (enzyme that aids
in breaking down lactose (milk sugar)
Turner Syndrome
 Unpaired X chromosome
 Many associated health and reproductive problems
Huntington’s Disorder
 Huntington's disease, chorea, or disorder (HD), is
a neurodegenerative disorder that affects muscle
coordination and leads to cognitive decline and
dementia
 Caused by a gene mutation
 Symptoms may not appear until later in life.