7-3 Human Genetic Disorders

- The harmful effects produced by mutated ggenes are called genetic disorders.

- Some genetic disorders are:

Disorder	Symptom	Defect	Gene
Cystic Fibrosis	Mucus clogs lungs, liver and pancreas, usually don't survive to adulthood	Failure of chloride ion transport mechanism	Recessive
Sickle Cell Anemia	Poor blood circulation	abnormal hemoglobin molecules	Recessive
Huntington's disease	Gradual deterioration of brain tissue in middle age; shortened life expectancy	Production of an inhibitor of brain cell metabolism	Dominant
Hemophilia	failure of blood to clot	defective form of blood clotting factor	sex-linked recessive
Phenylketonuria	failure of brain to develop in infancy; usually don't survive to adulthood	defective form of enzyme phenylalanine hydroxylase	recessive

- A Karyotype is a collection of chromosomees that can be used to determine abnormalities.

- If a person is born with to many chromosoomes (trisomy), they may cause abnormal development. Down syndrome is a form of trisomy in which three copies of chromosome 21 exist.

- By constructing and analyzing a pedigree,, a scientist can determine the pattern of inheritance of a trait within a family. It may also be possible to determine whether an individual is heterozygous or homozygous.

- The techniques involved in genetic counseeling can help identify parents at risk of having children with a genetic disorder. Current treatments for genetic disorders are beginning to include gene transfer therapy.