Download Human genetic disorders

Human genetic disorders
Coulter
Causes of genetic disorders
• Genetic disorder is an abnormal condition that a person inherits
through genes or chromosomes.
• Some genetic disorders are caused by mutations in the DNA of
genes.
• Other disorders are caused by changes in the overall structure or
number of chromosomes.
Cystic fibrosis
• Genetic disorder in which the body produces an abnormally thick
mucus in the lungs and intestines.
• The thick mucus fills the lungs making it difficult to breathe.
• Caused by recessive allele on one chromosome.
• The recessive allele causes three bases to be removed from on
DNA molecule (mutation)
Sickle-cell disease
• Affects hemoglobin, the protein in red
blood cells that carries oxygen.
• When oxygen concentration is low, the
red cells have an unusual sickle shape.
• These sickle shaped cells will clog
blood vessels and cannot carry as much
oxygen.
• The allele for sickle cell is
codominant.
• A person with one sickle cell allele and
one normal will have both types of
hemoglobin.
• A person with two sickle cell alleles
will have the disease.
Hemophilia
• Genetic disorder in which a persons blood clots very slowly or not
at all.
• Danger of internal bleeding from small bumps and bruises is very
high.
• Caused by a recessive allele on the X chromosome.
• Because it is a sex linked disorder it is more common in males
than females
Down syndrome
• A persons cells have an extra copy of chromosome 21.
• Instead of a pair of chromosomes, they have three.
• Most often occurs when chromosomes fail to separate properly
during meiosis.
• People with down syndrome have mental retardation, and heart
defects are common (can be treated).
pedigrees
• One important tool that geneticists use to trace the inheritance of
traits in humans is a pedigree.
• Pedigree is a chart or family tree that tracks which members of a
family have a particular trait.
pedigree
Horizontal line
represents a
union.
Vertical line
with a bracket
represents
children from
union
Managing genetic disorders
• Today, doctors use tools such as karyotypes to help diagnose
genetic disorders. People with genetic disorders are helped
through medical care, education, job training, and other methods.
karyotypes
• Is a picture of all the
chromosomes in a cell. The
chromosomes are arranged in
pairs.
• Karyotype can reveal if a
person has the right number of
cells.
• Look at this karyotype, does
this person have any disorders?
Genetic counseling
• Genetic counselors help couples understand their chances of
having a child with a particular genetic disorder.
• They use tools such as; karyotypes, Punnett squares, pedigree
charts to help in their work.
Dealing with genetic disorders
• Physical therapy helps remove mucus from the lungs of people
with cystic fibrosis.
• Folic acid; a vitamin, helps bodies of sickle celled people produce
red blood cells.
• Because of education and job training people with down syndrome
can work in hotels, banks, restaurants, an so on.