6.2 Human Genetic Disorders

Can you see if there’s an abnormality in this picture?

What is genetic disorder? Def: Abnormal condition that a person inherits through genes or chromosomes Ex. Cystic Fibrosis Sickle-Cell disease Hemophilia Down Syndrome

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.

Genetic Disorders Cystic Fibrosis : body produces abnormally thick mucus in the lungs and intestines, making it hard for the person to breathe. Caused by a recessive allele on one chromosome – result of a mutation.

Sickle-Cell disease: Red blood cells change to a sickle shaped cell, which can clog blood vessels. Codominant allele.

Hemophilia : sex-linked disorder Hemophilia : sex-linked disorder. Person’s blood will clot very slowly or not at all. Caused by a recessive allele on the X chromosome.

Down Syndrome – An extra copy of chromosome 21 Down Syndrome – An extra copy of chromosome 21. Some degree of mental retardation.– Caused during meiosis: chromosomes fail to separate properly.

Pedigrees An important tool that geneticists use to trace the inheritance of traits in humans – a chart or “family tree” that tracks which members of a family have a particular trait.

Managing Genetic Disorders * Karyotype : picture of all the chromosomes in a cell. Genetic Counseling: a couple that has a family history of a genetic disorder may turn to a genetic counselor for advice. Dealing with Genetic Disorders: Modifying an affected person’s environment – ex. Through medicine, diet, or education – can help manage some disorders. Sickle cell : take folic acid(vitamin) to help make red blood cells.