University of Iowa
Division of Medical Genetics
Testing Protocols

Huntington Disease: Presymptomatic Testing Outline

Objectives: Client will identify HD, why the individual is at risk and the absence of treatment

Client will identify why fetus at risk

A. Clinical Manifestations

HD handout

Information given to client to be relevant, current, to give informed, voluntary decisions

Give oral and written information

*Must have parent tested first

*Both parents agree to test, with the exception of rape

*Counseling to resolve disagreement

*No valid reason to do if unwilling to terminate

*Chorionic Villi Sampling or Amniocentesis with increased risk of spontaneous abortions

Autosomal Dominant Handout

No prevention or cure available at this time

No age of onset indicated from test

Affect on children and spouse, present and future

*Pregnant at present, documented?

*Prenatal Diagnosis

*Exclusion test?

Living with untreatable/non-preventable condition

Relationships may change

Testing may need to be delayed if there is a psych history which indicates it to be detrimental to do at present

Pedigree

Obtain blood sample from HD person

Must ascertain correctness of diagnosis (neurological assessment of family member may be necessary)

*Should do testing of parent first, potential for double grief

Ever received this diagnosis?

Neurological problems?

History of psychiatric treatment or substance abuse?

* Ability to parent

Objective: Client will identify how test will be done, time to get results, potential results and limitations of testing

A. Testing Protocol

Cost - sliding scale, R.G.C.S. only

Time table for appointments

At least one month from blood draw to appointment with results

Absolutely no results by phone

*Cost of Amniocentesis

*No future information given prenatally

Number of repeats, correlation between length and onset not well established

Change when passing through males

Blood draw may leave bruise

Informed consent signature obtained : 4 copies needed (patient, hospital record, lab, d-file)

Reference lab to be used has rigorous standards

No results can be obtained directly from lab

*Amniocentesis done at Fetal Diagnostics at U.I.H.C., S. Grant, R.N.

*Risks and time to get results

*Termination must be considered, would need to occur before end of 2nd trimester

Possible results-will actual number of repeats be given?

What reaction will you have?

Discuss error rate

*Can amniocentesis be contaminated with Mom?

No one under 18 (*Emancipated minors-self/prenatal testing?)

Will not give age of onset of symptons

Only to be used for test, no research uses

No communication with third parties without specific written consent from client

I. Withdrawal of Testing

If information is worse than not knowing, should not be tested

May decide at any time but if blood draw has occurred, results will be on chart

May bank blood for future testing for self or family

*Child consent to testing at age 18

Objective: Client will identify potential consequences of testing and results

A. Psychological

Any recent stressful events (divorce, separation)

Interests, hobbies, friends, colleagues

Suicidal ideation?

Current level of education

Present employment, any anticipated change?

Plans next 10 years? 20?

Potential problems for future

Any financial problems?

What is your present coverage?

Any anticipated change?

Potential problems for future

Marital Status? Length of relationship?

Any anticipated change?

What effect will the results have on the affected parent?

May divide family

May need blood samples from family members

Survival guilt

Results may indicate information about a person not being tested

Objective: Client will identify person or agency resource for support

A. Support Person

Questions for the Support Person

Relationship to client

Length of relationship

Shared difficult times? History of support

Any preconceived ideas about whether the client has inherited the HD gene?

Anticipated reaction of client

Need to be there pretest to postest

How will you provide support?

Who will you turn to?

Confidentiality

*Support person could be each other if a couple

*Any preconceived ideas about therapeutic abortion?

Questions for the client about the support person

Identify a person who is not also at risk to be with you

Who has helped you in the past

*Similar impact on each member if a couple

*Guilt to parent with HD gene

What is available to you?

Community resources

C. Support Groups

H.D.S.A. pamphlet, give addresses and phone numbers

What will you do the day, the next week, the next month, year after results?

Phone call the week of results, one month later

Yearly follow up as needed

Follow up provided by R.G.C.S. and U.I. Division of Genetics

Genetic counselors responsible for planning

Same counselor present for counseling and presentation of results

*These items are to be addressed with clients who are pregnant and seeking prenatal testing

Testing Documentation Educational Materials

Date of Blood Draw and sent to lab HD pamphlet

Date Results Received HD society pamphlet

Date Results Given to Client Autosomal Dominant handout

Copyright 1997, University of Iowa, Division of Medical Genetics

Copyright © 2010, ISONG