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Lesson 1

What Is a Rare Disease?


At a Glance


Lesson 1 asks students to consider their feelings about rare diseases and their attitudes toward people affected by a rare disease. Students are presented with a fictional scenario in which a reality TV show is thinking about filming a student with a rare disease joining the class. A short list of questions elicits students’ preconceptions about disease and its causes. Students distinguish between diseases that can be cured and those that can be controlled.

Major Concepts

  • Diseases have three main causes:
    – genetics,
    – environmental exposure, and
    – infectious agents.
  • Rare diseases may become common, and common diseases may become rare.
  • Some rare diseases can be cured, while many others can be managed through treatment.
  • People with a rare disease sometimes must cope with the stigma associated with their condition.


After completing this lesson, students will have

  • recorded their preconceptions about the nature of disease and
  • considered their feelings about people who are affected by rare diseases.

Teacher Background

Consult the following sections in Information about Rare Diseases and Scientific Inquiry:

1.0 A History of Rare Diseases in the United States
2.0 The Impact of Genomics on Rare Diseases
3.0 Rare Infectious Diseases
4.0 Rare Diseases Caused by Environmental Toxins

In Advance

Web-Based Activities
Activity Web Component?
1 No
Photocopies, Transparencies, Equipment, and Materials
Photocopies and Transparencies
1 transparency of Master 1.1
1 copy of Master 1.2 for each student
Equipment and Materials

Each student will need to maintain a notebook or folder dedicated to this supplement. Most lessons involve handouts and ask students to record information in their notebooks. The lessons also include opportunities for students to record their initial ideas and answers to questions about rare diseases and scientific inquiry. To help them monitor their own understandings and track how their thinking has changed, students will frequently refer back to their previous work and their initial understandings. Decide what format will work best for your students. If your students normally use bound composition books, they can continue to use these and tape or staple handouts into the book. Alternatively, students can use notebook paper for their writing, and then keep their notes and their handouts in binders or folders.


Activity 1: What Is a Rare Disease?

Estimated time: 50 minutes

Note: During this lesson, students have an opportunity to express their initial ideas about rare diseases and consider their feelings toward people who are coping with rare diseases. The lesson begins with a reality TV show scenario where a student with a rare disease is about to join the class. The aim of this scenario is to bring the idea of rare diseases into students’ lives. The intent of the lesson is not to teach content about rare diseases and their causes and management, but rather to elicit students’ prior knowledge about rare diseases. Responses to the questions posed during the lesson can help you assess students’ relative familiarity with the concepts and identify misconceptions. Intended to be brief, this initial assessment of preconceptions can help you adjust your teaching of Lessons 2 through 5.

  1. Begin the lesson by explaining that you have received a letter from a television producer asking for help with a new reality TV show his production company is developing.

  2. Display Master 1.1, Letter from a Producer. Ask for a volunteer to read the letter aloud to the class.
    The letter explains that a proposed reality TV show will take place in a middle school and involve a class that includes one student who has a rare disease. The show will give viewers an idea of how this student interacts with teachers and other students. The specific nature of the disease has not yet been decided.

  3. Further explain that the principal has asked your class to help with the producer’s request. Ask,
    • “How would you feel about having such a student join the class?”
    • “What questions would you want to ask before the student arrives?”
    • “What questions would you want to ask the student who has the rare disease?”

      Write these three questions on the board.

  4. Instruct students to record these questions and their answers to them in their notebooks. They should also record any feelings they have about the student joining their class.
  5. This step is intended to have students briefly record their initial feelings about people with rare diseases and to elicit any questions or concerns they might have. Give students about five minutes to complete this task.

  6. After students have recorded their thoughts and questions, ask for one or two volunteers to share something they wrote in their notebooks.
    At this time, accept all answers. Do not attempt to answer the students’ questions or make judgments about their feelings.
  7. image1
    Students’ responses to these questions will help you assess their initial attitudes toward rare diseases and those affected by them.

  8. Comment that the feelings expressed and the questions asked are understandable and that students will be learning about rare diseases during the remainder of this lesson and in the four lessons that follow.
  9. Explain that you will begin by exploring what the word “disease” means to them. Give each student a copy of Master 1.2, Thinking about Disease. Instruct students to answer the questions and carry out the task described on the handout.

    Explain that this handout is not meant to be a test. Instead, it is designed to help students organize their thinking about disease. Students’ responses to the handout will identify their preconceptions about disease. Give students about 10 minutes to complete the handout.

Note: Students may ask questions that, although good, address issues that interrupt the flow of the lesson. One strategy for honoring such questions is to establish a “parking lot” on a piece of chart paper or the board. One half of the parking lot is labeled “unanswered” and the other half is labeled “answered.” Questions that are best answered at a later time are written on sticky notes and placed in the “unanswered” column. As questions are addressed in the activities, move the sticky notes to the answered side of the parking lot.

  1. After students have completed Master 1.2, ask for volunteers to share their responses to Questions 1–3.

  2. Answer key for questions on Master 1.2, Thinking about Disease

    1. What is a disease?

      Many students will respond that a disease is a sickness that results from an infectious agent such as a germ, bacterium, or virus. If other causes such genetics or exposure to environmental toxins are not mentioned, do not be concerned. These other disease causes will be brought out in Question 3 and in the next lesson.

    2. How do doctors tell whether someone has a disease?

      Students will likely think of blood or other types of laboratory tests. This question also provides an opportunity to discuss different types of disease symptoms such as fever, pain, and skin rashes. Ask students to describe how the doctor can observe or measure these symptoms.

    3. What do you think causes disease?

      Again, students likely will mention infectious agents. If they don’t mention other causes, challenge them to think of a disease caused by something other than an infectious agent. If necessary, ask guiding questions to bring out the ideas that heredity and exposure to toxic substances in the environment are also causes.
Content Standard C: Disease is a breakdown in structures or functions of an organism. Some diseases are the result of intrinsic failures of the system. Others are the result of damage by infection by other organisms.

  1. Ask students to report some of the diseases they listed for Question 4 on the handout. As they respond, record and display for the class a list of about 20 diseases. After the list is assembled, ask students to think about the causes of these diseases and whether there are ways to group these diseases based on their causes. Instruct students to organize the 20 diseases in their notebooks in a way that illustrates the different causes.

    Students may elect to make a table with the columns corresponding to different causes and the rows corresponding to disease examples. Some students may be concerned that a given disease could have or be influenced by more than one cause. Ask these students to consider using a graphical representation such a Venn diagram to illustrate these interactions.

    Students may have listed diseases for which they don’t know the causes. This is understandable. The important part of this exercise is not to compile a lengthy list of diseases and their causes but rather to give students a chance to express their preconceptions about diseases and their causes. If students ask you what causes a particular disease and you know the cause, tell them so they can classify it. If you don’t know the cause of the disease, instruct the student to put a question mark next to the disease and not to worry about classifying it by its cause.

Note: You may want to assign Step 9 (causes-of-disease organizer) as homework.

  1. After students have completed the task, ask for volunteers to describe how they organized the diseases in their notebooks. Ask each volunteer to explain the general causes of the diseases and to list an example for each. Ask whether any of the diseases have more than one cause or whether any of the listed causes interact with each other.

    Ask questions to clarify students’ thinking, but do not correct misconceptions at this time. The three main causes of disease (infectious agents, heredity or genetics, and exposure to environmental toxins) will be addressed in the subsequent lessons.

    Environmental exposure may be somewhat confusing. One can argue that a disease brought about by exposure to a pathogen is environmental since the pathogen is found in the environment. For our purpose, a disease caused by environmental exposure refers to a nonliving agent such as radiation, heavy metals, or a toxin produced by another organism.

The manner in which individual students organize the list of diseases will help you assess the student’s initial ideas about diseases and their causes and to identify misconceptions the student may have.
  1. Ask for volunteers to share their responses to Question 5.

    1. What does it mean to call a disease “rare”?

      Students’ responses will vary. If students struggle with this question, rephrase it by asking whether some diseases affect more people than others. You may mention that in this country, a disease is considered to be rare if 200,000 people or fewer have it. To help students make some sense of this number, you can mention that the U.S. population was about 311 million people in 2011.

  2. Ask, “Do you think that a disease that is rare always remains rare? Can a rare disease become a common disease?”

    Students’ responses will vary. If students don’t bring it up, ask guiding questions to bring out the idea of a new infectious disease such as swine flu that begins as a rare disease and then becomes common as it spreads.

  3. Ask, “Can a common disease become a rare disease?”

    If a student doesn’t mention this, direct the discussion to medicine’s ability to control or even eradicate some diseases. You may mention polio as an example of a disease that was once common but is now rare. Smallpox has actually been extinguished.

  4. Ask for volunteers to share their responses to Question 6 (whether the diseases they listed are curable, controllable, or not controllable).

    For many diseases on their lists, students will not be able to say whether they are curable, controllable, or not controllable. Bring out in the discussion examples of diseases that are curable, such as many bacterial infections, and others that are controllable, such as diabetes.

  5. Explain that some diseases are relatively easy to treat and others are more difficult. Ask, “What are some reasons that one disease might be more difficult to treat than another?”

    Students may focus on specific diseases. Try to get them to speak in general terms to address issues such as the amount of information known about the disease, the ease of diagnosis, and the amount of resources that society devotes to the study and treatment of the disease.

    Remind students to return Master 1.2 to their notebooks. They will revisit the ideas they recorded on the handout in a later lesson.

  6. Conclude the lesson by remarking that the lessons that follow will give students opportunities to reflect on the ideas brought out during this lesson and to modify their thinking if necessary.

Lesson 1 Organizer

Activity 1: What Is a Rare Disease?
Estimated time: 50 minutes
Page and Step
Explain that a TV producer wants to film a reality show about a student with a rare disease joining the class. Display Master 1.1, and have someone read it aloud. Page 47
Steps 1
and 2
Write these questions on the board as you ask them:
  • “How would you feel about having such a student join the class?”
  • “What questions would you ask before the student arrives?”
  • “What questions would you ask the student who has the rare disease?”
Page 47
Step 3
Instruct students to write the answers in their notebooks. Page 47
Step 4
Ask one or two volunteers to share their answers with the class. Page 48
Step 5
Explain that students will be learning about rare diseases in the lessons that follow. To begin, they will explore the nature of disease.
  • Hand out a copy of Master 1.2 to each student.
  • Instruct students to follow the directions on the handout.
Page 48
Steps 6
and 7
Ask volunteers to share their responses to Questions 1–3. Page 48
Step 8
Ask volunteers to report diseases they listed for Question 4.
  • Record and display a list of about 20 diseases students mentioned.
  • Ask students whether they can group these diseases by cause.
Page 49
Step 9
Ask volunteers to explain how they grouped the diseases. Page 49
Step 10
Ask volunteers to share their responses to Question 5. Page 50
Step 11
Ask students,
  • “Do you think a disease that is rare always remains rare?”
  • “Can a rare disease become a common disease?”
  • “Can a common disease become a rare disease?”
Page 50
Steps 12
and 13
Ask volunteers to share their responses to Question 6. Page 50
Step 14
Explain that diseases vary in how easy they are to treat. Ask, “What are some reasons that one disease might be more difficult to treat than another?” Page 50
Step 15
Explain that students will be reflecting on these ideas and changing their thinking if necessary. Page 51
Step 16

= Involves making a transparency.     = Involves copying a master.

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