Download Genetic Counselors: Applying Key Concepts of Mendelian Genetics

Name_______________________________________
Date: _______________
Class: _____
Genetic Counselors: Applying Key Concepts of Mendelian Genetics to
Advise Families of Possible Risks of Genetics Disorders
Directions: For this assignment, you will work in groups of 2-3 students. You will be required to
analyze family histories and utilize the principles of Mendelian genetics to determine the likelihood of
a genetic disorder being inherited by a child for each family whose case you have been presented.
Each group will be assigned 2 different cases to examine. You will be required to put a booklet
together for each family whose case you are studying. You will then be required to present your
findings, as well as some information about the various genetic disorders.
CASE #2 – JENNY AND MARTIN
Jenny and Martin have been married for several years and have decided to have a child. Before
having any children, Jenny and Martin have decided to seek the advice of a genetic counselor to
determine the likelihood of their child having Huntington Disease, as it is common on Martin’s side of
the family. Martin does not know if he has Huntington Disease, as it does not appear until later in life.
He fears that he will pass it on to his child. Jenny and Martin have both provided their family history to
aid you in the examination of their case.
Martin’s side of the family:
Martin is the youngest of 5 children. He has 2 brothers and 2 sisters. 1 of his brothers and 1 of his
sisters have tested positive for Huntington Disease.
Martin’s father has Huntington Disease, but his mother does not have it.
Martin’s paternal grandmother does not have Huntington Disease. Martin’s paternal grandfather is no
longer living, but he did have Huntington Disease.
Martin’s maternal grandmother is no longer living and had Huntington Disease. Martin’s maternal
grandfather does not have Huntington Disease.
Jenny’s side of the family:
Jenny is an only child.
Jenny’s mother and father do not have Huntington Disease.
Jenny’s paternal grandmother and grandfather are both living, and neither has Huntington Disease.
Jenny’s maternal grandmother and grandfather are no longer living, but neither had Huntington
Disease.
Name_______________________________________
Date: _______________
Class: _____
Directions: Using the information provided by the family, it is now your job as genetic counselors to
examine the information provided, complete an analysis of the family history to determine the
likelihood of having a child with Huntington Disease, and provide the family with resources and
support services. The questions below will guide you as you work to find information about the
genetic disorder and complete the required analysis.
Part 1 – Background Research on the Genetic Disorder
1. What is Huntington Disease? Provide 2-3 pieces of information about the disorder.
Citation: ___________________________________________________________________________
2. What are the symptoms of Huntington Disease? Provide a complete list of known symptoms.
Citation: ___________________________________________________________________________
3. What are the effects on Huntington Disease? Provide at least 2-3 pieces of information.
Citation: ___________________________________________________________________________
Name_______________________________________
Date: _______________
Class: _____
Step 2 – Identification of the Disorder as Autosomal/Sex-Linked and Dominant/Recessive –must
have this section approved prior to moving to step 3
1. Is the disorder autosomal or sex-linked (x-linked)?
2. Is the disorder dominant or recessive?
3. What is/are the genotype(s) of a female with the disorder?
4. What is/are the genotype(s) of a male with the disorder?
5. Is it possible to be a carrier? If so, what is/are the genotype(s)?
Step 3 – Examine the family history through a Pedigree
**In the space provided, create a pedigree including all members of the family. Create a legend to
illustrate any of the following required by your pedigree: affected male, affected female, carrier male,
carrier female, unaffected male, unaffected female
Name_______________________________________
Date: _______________
Class: _____
Step 4 – Perform a Punnett Square to Determine the Likelihood/Probability of the Child having the
Genetic Disorder.
**Complete the Punnett Square in the space provided. Provide a probability for the child having the
genetic disorder.
Before completing the Punnett Square, determine the likelihood of Martin developing Huntington
Disease in the space below.
If Martin does develop Huntington Disease, what would his genotype be? ___________
Using the genotype above, complete a Punnett Square to determine the probability of having a child
with Huntington Disease if Martin does have the disease. (**If he does not have it, the child cannot
develop it)
Probability of Child having Genetic Disorder:_________ %
Step 5 – Support Services Available
1. Identify 2 different support services/resources available for couples with a child with the
genetic disorder above. These can be organizations, charities, medical facilities, etc that
provide aid and support.
a.
b.
Step 6 – Family Booklet
Create a booklet for the family that contains the information listed below in an organized manner. Be
prepared to present this information to the parents.
6. Provide all relevant background information about the disorder, its symptoms, and its effects.
(Step 1)
7. Provide the finalized pedigree with a legend for the family to examine. (Step 3)
8. Provide the Punnett square with the probability of the child having the genetic disorder.(Step 4)
9. Provide at least 2 support services for the family. (Step 5)
**All booklets must be handmade. You will be graded on the accuracy of the content and neatness*