This document discusses several human genetic disorders including cystic fibrosis, sickle-cell disease, hemophilia, Huntington's disease, and Down syndrome. Genetic disorders are abnormal conditions caused by mutations in genes or chromosomes that are inherited or can be passed down from parent to offspring. The document describes the causes and symptoms of each disorder and current treatments. It also discusses tools used to diagnose genetic disorders like amniocentesis, karyotypes, and the role of genetic counseling in assessing family histories and risks.

1. HUMAN GENETIC
DISORDERS

2. What are Genetic Disorders?
 Genetic disorder- an abnormal condition that
a person inherits through genes or
chromosomes
 Genetic disorders are caused by mutations
 The mutation may occur when sex cells form
or may be passed down from parent to
offspring

3. Cystic Fibrosis
 Body produces abnormally thick mucus in the lungs
and digestive system
 Symptoms:
 Difficulty breathing
 Bacteria in lungs can cause infections
 Digestive problems
 Mutation is caused by a recessive allele
 Most common in people of northern European
descent
 Currently no cure
 Treatment:
 drugs to prevent infection
 physical therapy

4. Sickle-Cell Disease
 Red blood cells are sickle shaped, resulting from
abnormal production of the protein hemoglobin
 Hemoglobin is responsible for carrying oxygen in the
blood
 Symptoms:
 Lack of oxygen in the blood
 Pain and weakness
 Most common in people of African descent
 Currently no cure
 Treatment:
 Drugs to relieve symptoms and to prevent blockages

5. Hemophilia
 A genetic disorder in which a person’s blood clots
very slowly or not at all due to a missing
protein
 Potential to bleed to death from small cuts or
minor bumps and bruises
 Caused by a recessive allele on the X
chromosome
 Occurs more frequently in males
 Treatment:
 Regular doses of missing protein
 Avoid contact sports

6. Huntington’s Disease
 A genetic disease that causes the gradual
breakdown of cells in the brain
 Caused by a dominant allele
 Is a fatal disease with no cure
 Symptoms appear around age 30

7. Down Syndrome
 A genetic disorder caused by an extra
chromosome 21
 The extra chromosome is a result of an error
during meiosis
 Symptoms:
 Distinctive physical appearance
 Some degree of mental retardation
 Heart defects

8. Diagnosing Genetic Disorders
 Scientists use tools such as
 Amniocentesis
 Doctor uses a long needle to remove fluid surrounding
the baby
 Fluid contains cells that are analyzed in a karyotype
 Karyotypes
 A picture of all the chromosomes in a cell
 Doctors arrange chromosomes in pairs
 Look for correct number and shape of
chromosomes
 Can be used to determine sex of baby

9. Genetic Counseling
 People may have genetic counseling if they
have a history of genetic disorders in their
families
 Genetic counselors use karyotypes, pedigree
charts, and Punnett squares to determine a
couple’s chances of having a child with certain
genetic disorders