Problem Solving in Genetic Disorders*

Sau-Ha (Nikki) Chen
1994 Woodrow Wilson Biology Institute

Introduction

All of us can attribute our finer characteristics to genetic lineage. We also may encounter the adverse effects of inheritance in different members of our family, friends and acquaintances. Our basic understanding of genetics answers these questions about our genetic heritage. This activity uses case histories to study genetic disorders and it tests students' knowledge of heredity. These case studies reinforce their understanding of genetic principles.

Concepts and skills covered in this activity

• the causes and effects of genetic disorders
• the phenotype and genotype of individuals
• the prediction of recurrence risks
• the use of the Punnett square
• the construction of pedigree charts

B. Skills

• the process of asking appropriate questions
• the use of available resources outside of the school (i.e., health and research organizations)
• the use of critical thinking skills
• the forming of conclusions
• the learning and refining of social skills (i.e., cooperation, responsibility, compassion, patience, etc.)

C. Careers

• genetic scientist
• genetic counselor
• medical geneticist
• science teacher

Teacher Information

Background

• chemical building block level - lactose intolerance, familial hypercholesterolemia, Lesch-Nyhan syndrome
• organelle level - Tay-Sachs disease, Hurler disease
• cellular level - cystic fibrosis, neurofibromatosis, progeria
• chromosomal level - Down's syndrome

Target group:biology students

Time: 4 - 6 weeks (allow ample time for institutions to respond to your students' requests) Instruct students to send for information from various institutions as soon as possible. Introduce and set up this activity at the beginning of the genetics unit. As the content in genetics evolves, their understanding of their problems is revealed. The activity is used as a culmination of the unit.

Teacher procedures

This activity can be used concurrently with the activities, "One + One = One" by Dorothy Josephine Cox and "The Genetics of Parenthood" by Lenore Kop and Thomas Crowley. Combining the three activities personalizes the problem and expands the learning experience. As students are separated into groups, give each group a cooked or uncooked egg. The egg is their fragile child. They are to carry and care for the egg for one week without damaging the egg (child). (Refer to "One + One = One" for further details) The facial characteristics of the child are decided by using Mendelian principles (refer to "The Genetics of Parenthood").

**Note to teacher: If you do this activity alone, omit procedure #3 on the "student worksheet."

Case History

My husband's father and his sister have sickle cell disease. My aunt also has the same disorder. What is the risk of this child having the sickle cell disease? My husband's company is sending him to E. Africa for two years. Our newborn baby and I are going with him. We just heard on the news that the region we are moving to has an outbreak of malaria. How likely are we to become infected by malaria?

We are happy and concerned because my wife's brother and my maternal cousin have hemophilia A. Are my wife and I both carriers of hemophilia A? How can we find out? We already have a happy, healthy little girl. Is she really O.K.? My neighbor who recently moved from Israel has a son with factor XI deficiency. He bleeds easily and excessively when injured. Is there a connection to hemophilia A?

My wife has just turned 40 and I am 45 years old. This is our first child. We did not undergo any prenatal test for any disorders. This might have been a mistake. The new neighbors next door have a Down's syndrome infant. They are about our age. My wife's father was recently diagnosed as having Alzheimer's disease. What is the chance that our daughter has Down's syndrome? Is there a connection between my father-in-law's illness and Down's syndrome? How can we find out for sure?

All vital signs are normal at this time. You are concerned though because your oldest son is 10 years old and was diagnosed as having cystic fibrosis while you were pregnant with your third child. Your second son is a perfectly healthy child. You wonder whether this third child has cystic fibrosis. You were told your distant cousin had cholera. Is there a connection between cystic fibrosis and cholera?

My maternal grandfather as well as an aunt and an uncle had Huntington's disease. My mother is showing signs of the disorder. My brother and I appear to be normal at this time. We both are in our twenties. He has two children and they seem to be very healthy. This child is our first. My husband is concerned as to whether this son and I have inherited the Huntington's gene. Is there a test for this disorder? Is Hunter syndrome a shortened form of Huntington's disease?

My husband's mother and her father died of amyotrophic lateral sclerosis within five years of diagnosis. My husband is in his twenties and shows no symptoms of ALS. This is our first child and we are happy with this blessed event. In the back of our minds, we both wonder whether this child can inherit this disorder. How can we find out? Is there a connection with Lou Gehrig's disease? Does this have anything to do with multiple sclerosis?

Four out of six of our children are known as troublemakers in school. We are constantly being contacted by their teachers and principals. The oldest child and the fourth child are boys. They have an annoying habit of repeating what was said to them. They are punished constantly for yelling out obscenities in school. We tried to teach them right and wrong, but it is not working. The second and third children are girls and they get into trouble in other ways. They just could not sit still and they are always fidgeting, jerking their heads, blinking and grimacing. Other than that, the two girls are good students. They manage to get good grades. Our two youngest, a boy and a girl are perfectly healthy, normal children. Will this seventh child be healthy and normal? Our niece and nephew on the husband's side also display peculiar behavior. The niece takes about twenty showers a day and the nephew has dyslexia as well as problems solving simple mathematical problems. An aunt from the wife's side has schizophrenia and she displays behavior like my children. We were watching a documentary on TV the other day, it talked about Tourette's syndrome. The subjects of the documentary reminded me of my children. Do my children have schizophrenia or Tourette's syndrome? How would we know?

My older brother died of familial hypertrophic cardiomyopathy when he was 34 years old. My mother, an aunt and my grandfather succumbed to heart failures in their thirties. I am 26 years old and appear to be normal. I am very athletic and love to play basketball. My wife is concerned because she heard that a basketball player in a major team had a heart attack during a game. The cause was "sudden death". She wants to know whether there is a connection between sudden death and hypertrophic cardiomyopathy. What is the risk of our son having one of these disorders?

We are pleased to welcome a new addition to our family. We are concerned because our first son who is 10 months older has just been diagnosed as having Lesch-Nyhan syndrome. We really don't known much about this disorder. Does it mean this little girl has the same disorder? My maternal cousin just told me that her son was diagnosed as having cerebral palsy. Is there a connection between cerebral palsy and Lesch-Nyhan syndrome?

In my extended family, seven of the twenty-four cousins have neurofibromatosis Type 2. Of the seven cousins, three were females. Six of the affected cousins had a parent who is hearing impaired. Our grandfather died of a brain tumor and was deaf in both ears. My mother died of a brain tumor when I was very young. My sister and I appear to be normal. My oldest son also appears normal but my second son is hearing impaired. Will this child inherit neurofibromatosis Type 2?

My father, sister, and one of my nephews are red-green colorblind. My husband and I are not colorblind but the older of two sons is colorblind. Will this little girl inherit colorblindness?

All vital signs appear normal except the boy has cleft lip with cleft palate. My husband has cleft lip and so does my brother. We want to have more children. What is the risk of having another affected child? Does this have anything to do with harelip?

Before birth, an amniotic fluid test showed a high concentration of alpha-fetoprotein. What does this mean? There was also mention made of meningomyelocele and anencephaly. What will happen to our son?

All vital signs appear normal at this time. However, the doctor said that the diaper test for Phenylketonuria (PKU) is positive. We have an appointment to meet with him later this week. We hope that it isn't like that boy who lived in the bubble (A-Gammaglobulinemia), but we think we'll check that out too.

My 24-years-old sister, a gymnast, died suddenly of a ruptured aorta during a competition. My younger brother is nearsighted and nicknamed "gorilla" by his friends because of his unusual features. He was diagnosed as having Marfan's syndrome. He was told a famous president also had the same disorder. I am considered to be tall for a woman and my husband is about the same height. I was told by my doctor that I have a weak heart. Do I have the same syndrome as my brother? And what about my little girl?

Tests performed immediately after birth show that our son may have the "Christmas disease." Is this because this child was born on Christmas Day? Or does this have to do with hemophilia, since cases existed in our family history?

1. To study the causes and symptoms of genetic traits
2. To understand how genetic traits are inherited
3. To experience the responsibility involved in having an unhealthy child

Procedures:

1. Students work in groups of two (parents) or work alone (single parent). Follow instructions from the teacher.
2. Each group or single parent is expecting a child. Obtain a case history of your child from your teacher.
3. Obtain an egg from your teacher. Care and carry your egg (child) for one week without damaging it. Share the responsibility with your partner. The egg should not be left unattended. For example: Do not leave your child alone in your bedroom or locker. If you cannot take your child to class, consult a good baby sitting service. Draw the facial characteristics of your child on the egg. See your teacher for further instruction.
4. Research the inherited trait(s) described in your case history. Use the local telephone book, library references for names of institutions, organizations and hospitals to obtain resource materials. Contact these places as soon as possible since it will take time for them to respond. Interview doctors, nurses, genetic counselors or people who are afflicted with the genetic disorder. Use the information guideline given as a starting point. As you become more knowledgeable in your research, you will know what questions to ask, what information you need and where to obtain this information.
5. Submit an outline or briefly describe your findings on the assigned date to the teacher.
6. Prepare an oral and written presentation for the due date. Your presentation can be in the form of pamphlets like those found in doctors' offices or be an informative poster or a video presentation. Check with the teacher for other ideas. Be CREATIVE!
7. Individually, write a paragraph or two describing your experience. Express your feelings about this activity. Avoid statements such as "It was fun!", and "I learned a lot." Elaborate on your thoughts.

Information Guideline:

I. Genetic trait/problem:

II. Cause(s):

III. Symptoms:

IV. Population affected: (sex, ethnic group, age, etc.)

V. How is it inherited? (sex-linked, recessive, dominant, etc.)

VI. Possible pedigree to show how your child inherited the trait or a Punnett square to show how the trait is passed on from generation to generation.

VII. Care, cure or prevention if any:

Note: As you become familiar with your problem, the suggested categories will increase.

Resources

Alzheimer's Association 70 East Lake Street 1717 Massachusetts Avenue NW, Suite 305 Chicago, IL 60601-5997 1-800-621-0379	Asthma and Allergy Foundation of America 1717 Massachusetts Avenue NW, Suite 305 Washington, D.C. 20036 (202) 265-0265
American Cancer Society 1599 Clifton Road, NE Atlanta, GA 30329	Cooley's Anemia Foundation 420 Lexington Ave. New York, NY 10017 212-697-7750
American Diabetes Association 1660 Duke Street Alexandria, VA 22314	Committee to Combat Huntington's Disease 250 West 57th St. New York, NY 10119 212-757-0443
American Heart Association 7320 Greenville Avenue Dallas, TX 75231 (214) 373-6300	Cystic Fibrosis Foundation Suite 309, 6000 Executive Blvd. Rockville, MD 20852 301-881-9130
American Liver Foundation 1425 Pompton Avenue Cedar Grove, NJ 07009 1-800-223-0179	Epilepsy Foundation of America Suite 406, 4351 Garden City Drive Landover, MD 20785
American Lung Association 1740 Broadway New York, NY 10019-4374 (212) 315-8787	Leukemia Society of America 733 Third Avenue New York, NY 10017 212- 573-8484
American Social Health Association P.O. Box 13827 Research Triangle Park, NC 27709 (919) 361-8400	March of Dimes 1275 Mamaroneck Ave. White Plains, NY 10605
Amyotrophic Lateral Sclerosis Association 21021 Ventura Boulevard, Suite 321 Woodland Hills, CA 91364	National ALS Foundation 185 Madison Avenue New York, NY 10019
Arthritis Foundation 1314 Spring Street Atlanta GA 30309 1-800-283-7800	National Association for Sickle Cell Disease 3460 Wilshire Blvd. Los Angeles, CA 90010 213-731-1166
National Fnd. for Jewish Genetic Diseases 609 Fifth Ave. New York, NY 10017 212-753-5155	National Retinitis Pigmentosa Foundation 8331 Mindale Circle Baltimore, MD 21207 301-655-1011
National Genetics Foundation 555 West 57th St. New York, NY 10019	National Society to Prevent Blindness 500 East Remington Road Schaumberg, IL 60173 (708) 843-2020
National Hemophilia Foundation 19 West 34th St. New York, NY 10001 212-563-0211	Natl. Sudden Infant Death Syndrome Assn. 8200 Professional Place, Suite 104 Landover, MD 20785 1-800-221-SIDS
National Mental Health Association 1021 Prince Street Alexandria, VA 22314-2971 (703) 684-7722	Muscular Dystrophy Association 810 Seventh Ave. New York, NY 10019 212-586-0808
National Multiple Sclerosis Society 205 East 42nd Street New York, NY 10017-5706 (212) 986-3240	The National Kidney Foundation 30 East 33rd Street New York, NY 10016 1-800-622-9010
National Organization for Rare Disorders P.O. Box 8923 New Fairfield, CT 06812 (203) 746-6518	United Cerebral Palsy Associations 66 East 34th Street New York, NY 10016 1-800-USA-ICUP
National Osteoporosis Foundation 2100 M Street N.W., Suite 602 Washington, DC 20037 (202) 223-2226

Toll-Free Health Hotlines

Additional resources can be obtained from your state health officials. Another excellent source of information is in the appendix of The Family Genetic Sourcebook by Benjamin A. Pierce. Also available a CD-Rom software produced by Creative Multimedia. Contact Apple Computer, Inc.

References:

*Adapted from an idea from Judy Brook.

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