7-3 Genetic Disorders

Vocabulary

and

Graphic Organizers

Mutation

A change in a gene. In some cases, genes are sometimes damaged or copied incorrectly.

Most mutations are recessive and are not

expressed in the heterozygous condition

The mutation will only be expressed if both parents pass on the

recessive gene.

Harmful mutations can cause genetic

disorders

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Genetic disorder

Harmful effects that are produced by

mutations

In most cases genetic disorders are recessive

Sickle cell anemia

Cystic fibrosis

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Hemophilia

Down syndrome

Cystic fibrosis

Recessive genetic disorder caused by a mutation in a gene

that codes for a transport protein

In the homozygous condition – causes cells in respiratory

and digestive systems to produce misshapen transport

proteins

Gene Therapy

Mucus forms in the lung and pancreas

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located the gene that causes Cystic fibrosis.

Patients have trouble breathing and digesting

their food

Gene Therapy

Healthy copy of the mutated gene is

transferred into the lungs of cystic fibrosis

patients

The possibility is still in the stages of research

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This could be a potential cure in the

near future

Sickle cell anemiaRecessive gene

disorder caused by mutation in the gene

that codes for hemoglobin

Hemoglobin is the protein in red blood cells that moves

oxygen throughout the body

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Causes low blood iron, fatigue,

headaches, muscle cramps

Heterozygous condition is resistant

to Malaria

Hemophilia

Recessive genetic disorder caused by a

mutation on the X chromosome

Causes the body to build a defective form of a protein

needed to clot blood

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Small cuts are difficult to heal and

internal bleeding could be fatal

Carried on the X chromosome. Women are carriers, while men

will develop the disorder

Sex-linked inheritance

Sex-linked inheritance

Traits that are determined by genes

located on the X chromosome

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Down syndrome

Arises from 3 copies of chromosome 21

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Physical characteristics:Extra folds in upper eyelids, broad and

flattened nose, thick tongue, and mental

retardation

Occurs in about 1 of every 1000 births

Genetic Counseling and Gene Therapy

Carrier

Person who is heterozygous for recessive mutation. They are

known as a carrier of the gene.

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If one member of the family has a genetic disorder, it is possible

that other members of the family have the recessive gene.

Genetic Counseling

pedigree

A pedigree is a record that shows inheritance patterns over

several generations

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A Genetic counselor will look for a pattern in the family history of genetic

disorders to try and determine whether the client is at risk of having children

with a genetic disorder

Genetic Counseling

Kids – to have, or not to have