Health: Genetics and Inherited Conditions
Understanding inheritance, risk, and healthy decision-making
Health: Genetics and Inherited Conditions
Understanding inheritance, risk, and healthy decision-making
Health - Grade 9-12
- 1
Define the terms gene, allele, and inherited condition in your own words.
A gene is a section of DNA that helps determine a trait or body function. An allele is a version of a gene. An inherited condition is a health condition that can be passed from parents to children through genes. - 2
Cystic fibrosis is usually inherited in an autosomal recessive pattern. Two parents are both carriers, which means each has one normal allele and one cystic fibrosis allele. Use C for the normal allele and c for the cystic fibrosis allele. What are the possible genotypes for their child, and what is the chance the child will have cystic fibrosis?
Set up a 2 by 2 Punnett square with C and c from each parent.
The possible genotypes are CC, Cc, Cc, and cc. There is a 25% chance the child will have cystic fibrosis because only the cc genotype causes the condition. - 3
Explain the difference between a dominant inherited condition and a recessive inherited condition.
A dominant inherited condition can appear when a person has just one disease-causing allele. A recessive inherited condition usually appears only when a person has two disease-causing alleles, one from each parent. - 4
Huntington disease is often described as an autosomal dominant condition. If one parent has one Huntington allele and one normal allele, and the other parent has two normal alleles, what is the chance that each child will inherit the Huntington allele?
Represent the affected parent as Hh and the unaffected parent as hh.
Each child has a 50% chance of inheriting the Huntington allele. This is because the affected parent can pass either the Huntington allele or the normal allele. - 5
A person has one recessive allele for sickle cell disease and one normal allele. Explain why this person is called a carrier and whether they usually have the disease.
This person is called a carrier because they carry one allele that can be passed to a child. They usually do not have sickle cell disease because the normal allele helps produce enough typical hemoglobin function. - 6
A couple is considering having children. One partner has a family history of Tay-Sachs disease, and the other partner does not know their family history. List two health-related steps they could take to learn more about genetic risk.
Think about reliable sources of medical information and testing options.
They could talk with a healthcare provider or genetic counselor about their family history. They could also consider carrier screening to learn whether either partner carries a Tay-Sachs allele. - 7
Explain why family health history can be useful even when a condition is not caused by a single gene.
Family health history can show patterns of risk for conditions influenced by many genes and shared environments. It can help a person and healthcare provider make choices about screening, prevention, and lifestyle. - 8
Some conditions, such as type 2 diabetes and heart disease, are multifactorial. Explain what multifactorial means in genetics and health.
Break the word into multi, meaning many, and factor, meaning cause or influence.
Multifactorial means that a condition is influenced by more than one factor. These factors can include many genes, diet, physical activity, stress, sleep, environment, and access to healthcare. - 9
Hemophilia A is often inherited in an X-linked recessive pattern. Explain why X-linked recessive conditions are more common in males than in females.
X-linked recessive conditions are more common in males because males usually have one X chromosome and one Y chromosome. If their single X chromosome has the disease-causing allele, they do not have a second X chromosome with a normal copy to balance it. - 10
A genetic test can show whether a person has a higher risk for certain inherited cancers. List two benefits and two possible concerns related to genetic testing.
Consider both medical usefulness and personal or social effects.
Two benefits are that testing can help guide screening and prevention, and it can help family members understand possible risks. Two concerns are that results may cause stress, and privacy or insurance concerns may need to be discussed with a qualified professional. - 11
A student says, 'If a condition is genetic, there is nothing a person can do about it.' Write a response that corrects this statement.
This statement is not fully correct. Some genetic conditions cannot be prevented, but people may still be able to manage risk through screening, treatment, lifestyle choices, medications, or early medical care. - 12
Create a short explanation for why genetic information should be kept private and shared carefully.
Think about consent, privacy, and how information may affect relatives.
Genetic information should be kept private because it can reveal health risks about a person and sometimes their relatives. It should be shared carefully with trusted healthcare professionals and family members when it supports informed health decisions.