1. Ch 6, Sec 2 Human genetic disorders
Genetic Disorder - an abnormal condition that a person inherits through genes or chromosomes Causes of Genetic Disorders - *Some genetic disorders are caused by changes in the DNA of genes. Other disorders are caused by changes in the overall structure or number of chromosomes

2. Common Genetic Disorders - Cystic Fibrosis - body produces abnormally thick mucus in lungs & intestines - caused by recessive allele on chromosome #7, from a mutation of 3 bases removed from a DNA molecule - Sickle-Cell Disease - affects hemoglobin, a protein in red blood cells that carries oxygen - the shape of the red blood cells are sickle, clogging blood vessels and not able to carry enough oxygen

3. - sex-linked disorder, chromosome #23
- Sickle-Cell Cont’d
- chromosome #11
- a person with both sickle cell alleles will show the disease, a person with one sickle-cell allele and one normal produce both normal hemoglobin & abnormal hemoglobin, but not show symptoms of disease
- Hemophilia
- sex-linked disorder, chromosome #23
- blood has difficulty clotting, protein not created by body that facilitates clotting
- internal bleeding from bumps/bruises
- caused by recessive allele on X chromosome

4. Down Syndrome - extra copy of chromosome 21 (3 instead of 2) - occurs most often when chromosomes fail to separate properly during meiosis - causes some degree of mental retardation Pedigrees - a chart or “family tree” that tracks which members of a family having a particular trait - Important tool used by geneticists to trace inheritance of traits in humans

5. Managing Genetic Disorders
- today Dr’s use a karyotype (tool)to help
diagnose genetic disorders.
Karyotype
- a picture of all the chromosomes in a cell
- chromosomes are arranged in pairs
- can reveal whether a person has the correct
number of chromosomes in his or her cells
- Genetic Counseling
- Dealing with Genetic Disorders
- modify diet, medicine, education on topic
- help couples understand their chances of having a child with a specific genetic disorder