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7.01 Genetics Meets "The Real World"

7.01 Genetics Meets "The Real World"

Written by Patti Soderberg, Beloit College, copyright 1995

Read the information below and construct a pedigree for the family described herein.

The genetics counseling community ascribes to a belief in non-directive counseling. That is, they feel that it is their duty to provide all of the information that is available and desired by a family so that they can make the decisions that are appropriate to them based on their own cultural, moral, religious, etc. beliefs. The genetic counseling community cringe when people have the misconception that what they do is to tell people what decisions to make and what course of action to take.


Marfan Syndrome Description

* Inherited as an autosomal dominant trait. (about 15% of cases may be due to new mutations)
* Defect of connective tissue formation.
* Some common features of the syndrome (not all are present in all cases): * It also causes heart valve abnormalities and weakening of the aortal wall. During heavy exercise, the weakened aortal wall can burst, leading to almost instantaneous death.
* There is, as yet, no genetic or biochemical test for this syndrome.

Anne's Family Tree:

Anne, a case study in Genetic Counseling:

Proband:

Anne:

Anne is 16 years old and is a junior in high school. She has read some information in the popular press on Marfan Syndrome and she and her parents are concerned that Anne might have this syndrome. Her general physician has referred her to the Genetics Counseling Clinic. Anne is 5' 11", and wears contact lenses to correct for myopia (nearsightedness). She plays on her school's varsity volleyball and basketball teams. NCAA scouts are already interested in her playing ability and there is a chance she will be offered college scholarships in both sports. Her armspan:height ratio is 1.08:1. (In one group of 27 adults, this ratio was 1.006 with standard deviation = 0.03.)

Siblings:

* David:
Age 25, married to Jessica, age 25, one daughter named Kristi, age 3 months. David wears glasses, is 6' 3", has long fingers and toes, played basketball and ran track in high school, had some knee problems that developed during his high school athletic career. Jessica is 5' 8", no glasses, no health complaints other than occasional migraine headaches. She and David had one miscarried pregnancy in the first trimester before the birth of Kristi.

* Cheryl:
Age 14, 5' 9", no glasses, has a slight case of scoliosis. She was born with club feet which responded well to corrective treatment.

Parents:

* Mary:
Age 47, 5' 7", wears glasses, has hay fever. Has been diagnosed with carpal tunnel syndrome and mild diabetes. Had two miscarriages in addition to her three children.

* Peter:
Age 49, 6' 1", wears glasses, concave chest, high blood pressure, partial lens dislocation in left eye, long fingers and toes. Has complained about chronic tennis elbow.

Aunts & Uncles:
Mary's Siblings:

* Dorothy:
Age 46, wears glasses, 5' 3", no major health problems. Has had an ovarian fibroid tumor removed at age 40. Married and has 4 children.

* Ellen:
Age 50, 5' 5", high cholesterol, has been diagnosed with irritable bowel syndrome. Unmarried, no children.

* Eric:
Age 51, 6' 1", wears reading glasses, has recurrent back problems from a car accident, suffers from exercise-induced asthma. Is married and has two children from his first marriage and three from his second.

Peter's Siblings:

* Frank:
Age 55, 6' 4", wears glasses, slight hearing loss in one ear. Was treated for alcoholism, is a heavy smoker and has developed a chronic cough. Divorced, the father of 2 children.

* Alice:
Age 56, 5'7", wears glasses, arthritis in left shoulder. Married, has one daughter and a son who was born with cerebral palsy.

* John:
Deceased, heart attack at age 46, 6'2", had dislocated lens in right eye. He and his wife had three children. Their youngest lives with his wife, who is still living, as she is slightly mentally retarded.

* Larry:
Age 58, 6'3", no glasses, high blood pressure. Divorced twice, lives alone now. Had two children by his first marriage and one by his second. Is a heavy drinker.

Grandparents

Anne's Maternal Grandparents

* Evelyn:
Died at age 76 of stroke, 5'4", arthritis in hands and feet, wore reading glasses. Was said to have had as many as 5 miscarriages.

* William:
Age 81, no glasses, 5'10", no major health problems. Has a slight limp due to a bad right knee, occasional rashes, and hemorrhoids.

Anne's Paternal Grandparents

* Gloria
Age 86, 5'8", high blood pressure, some knee and ankle problems. Is concerned about her constipation. Wears glasses for distance and reading.

* Charlie
Died at age 44 of a heart attack, severe vision problems, described as long and lanky. Contracted polio at age 26. has been wheelchair dependent since his polio treatment.


Who appears to possibly have Marfan Syndrome? What are the chances of their offspring having Marfan Syndrome? What medical information is important for people with Marfan Syndrome so that they can live a healthy and prolonged life? What are the ethical and social issues involved in this particular case for Anne and her parents?

[Repeated from the beginning of the page]
The genetics counseling community ascribes to a belief in non-directive counseling. That is, they feel that it is their duty to provide all of the information that is available and desired by a family so that they can make the decisions that are appropriate to them based on their own cultural, moral, religious, etc. beliefs. The genetic counseling community cringe when people have the misconception that what they do is to tell people what decisions to make and what course of action to take.


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