Young Leaders’ Program Colloquium Genetic Testing of Children for the Sake of Other Family Members: Ethical and Legal Issues (Nagoya University School of Medicine) Eiji Maruyama, Kobe University
Purpose of This Colloquium In this colloquium, I would like to discuss the ethical and legal problems of genetic testing of minors for the sake of other family members using a case report by professor Mariko Tamai of Shinshu University. Professor Tamai is a clinical psychologist at the Department of Clinical and Molecular Genetics of Shinshu University Hospital. Professor Tamai kindly gave me permission to use her materials in this colloquium.
Notes for Professor Tamai’s Case Professor Tamai’s Case is concerned with the genetic testing of two boys who were suffering from Duchenne type muscular dystrophy (DMD). DMD is a hereditary (X-linked recessive inheritance) muscle disorder with onset usually before age 6. Characterized by symmetric weakness and wasting of first the pelvic and crural muscles and then the pectoral and proximal upper extremity muscles. Progression is steady. Most patients are confined to a wheelchair by age 10 or 12 and used to die of respiratory complications by age 20 yr. However, recently with the help of a respirator some patients survive into their thirties.
X-linked Recessive Inheritance XY XX’ Normal Carrier XX XX’ XY X’Y XX Normal Carrier Normal Patient Normal XX’ XX’ XY XY Carrier Carrier Normal Normal
Professor Tamai’s Case (The following case was posted on her home page*, and with her permission, is quoted here with some changes.) Professor Tamai’s client, in her 40s at that time, had two male children. Both had been diagnosed as Duchenne muscular dystrophy (DMD) based on their neurologist’s clinical observations. The older boy was 14 year old. The younger one was an 11 year old. The client became pregnant unexpectedly. When she visited the clinical genetic department of Shinshu University hoping for a healthy baby, she was in the 10th week of pregnancy. [*http://square.umin.ac.jp/~mtamai/gene_info.htm]
Professor Tamai’s Case The client wanted to know if the fetus had DMD. She said that it would be too much for her to raise another child with DMD since she already had two with the disease. After careful considerations, she decided to visit Professor Tamai’s department. She had not told either of the boys about her pregnancy. In order to find out if the fetus had DMD, it was necessary to investigate the genes of both boys to identify the specific type of mutation. In this case, neither of the boys had been genetically tested.
Professor Tamai’s Case As a cause of the DMD, there are three types of mutation of dystrophin gene; deletion, duplication and point mutation. More than half of all the cases are due to deletion. If their mutation type was deletion, the fetus could be genetically tested using their genetic information. In order to obtain their genetic information, blood samples of both boys had to be taken.
Professor Tamai’s Case The client did not want to tell her boys about her pregnancy and the necessity of their genetic information. One week after the first visit, she came to the outpatient department with her two boys. She had told the boys only that they would go to the hospital for some tests. After some general checkups, blood samples were taken from them without telling them the nature and purpose of the test.
Question 1 For the purpose of prenatal diagnosis, is it acceptable to take a blood sample from the parents' other children (who are already born and suffering from the disease), use that blood sample to carry out an examination for genetic mutation related to the disease, then use the resulting genetic information to avoid giving birth to another child having the same disease? Suppose the child is 14, 11, 7 or 2 year old. Does the degree of youngness of the child affect your answer?
Professor Tamai’s Case After taking the blood from the boys, the information of their gene mutation was obtained. It identified the mutation as deletion. Then my client in the 15th week of pregnancy had an amniocentesis. The chromosomal test determined the fetus was female. As the X-linked recessive disorder usually appears only in a male person (a female fetus has 50 percent chance of being a carrier of the disorder), and the risk of the fetus having the DMD decreased to a negligible level, she continued her pregnancy and gave birth to an apparently healthy girl. The boys genetic information was not used at this stage.
Professor Tamai’s Case However, when the girl grows up and if she wants to know before her marriage whether she carries the same mutation as her mother and brothers, the information kept in each brother's file will be needed.
Question 2 If, 20 years later, the sister decides to find out whether she is a carrier of the dystrophin gene mutation, should her brother's genetic information be made accessible to her (her doctors) without her brothers’ informed consent? In the meanwhile, how should the parents and doctors behave toward her regarding this matter, anticipating she, someday, will become to like to know her own carrier status of the brothers’ disease.
Problems 1 . S h o u l d i t b e a l l o w e d t o p e r f o r m a g e n e t i c t e s t o f a m i n o r p a t i e n t s u f f e r i n g f r o m X - l i n k e d r e c e s s i v e d i s o r d e r s u c h a s D u c h e n n e m u s c u l a r d y s t r o p h y o n l y w i t h t h e c o n s e n t o f h i s p a r e n t s , w h e n t h e s o l e p u r p o s e o f t h e t e s t i s m a k i n g i t p o s s i b l e t o c o n d u c t p r e n a t a l d i a g n o s i s o f t h e f e t u s w h o , i f b o r n , w i l l b e h i s s i b l i n g , o r c a r r i e r t e s t i n g o f h i s f e m a l e ( a l r e a d y b o r n ) s i b l i n g s o r a u n t s ? I f i t i s a l l o w e d , w h a t j u s t i f i c a t i o n c a n b e o f f e r e d f o r i t ? 2 . I f t h e g e n e t i c t e s t o f t h e p a t i e n t h a s a l r e a d y b e e n d o n e , a n d u s i n g h i s g e n e t i c i n f o r m a t i o n , i t i s p o s s i b l e t o c a r r y o u t s u c h p r e n a t a l d i a g n o s i s o r c a r r i e r t e s t i n g , m a y i t b e u s e d o n l y w i t h t h e c o n s e n t o f h i s p a r e n t s ? I f s o , o n w h a t b a s i s i s i t p e r m i s s i b l e ?
Principles 1 . I n f o r m e d c o n s e n t I n o r d e r t o c a r r y o u t a g e n e t i c t e s t , i n f o r m e d c o n s e n t m u s t b e o b t a i n e d f r o m t h e i n d i v i d u a l t o b e t e s t e d . I f t h e p a t i e n t i s a y o u n g c h i l d a n d i n c o m p e t e n t t o g i v e h i s o w n c o n s e n t , p r o x y c o n s e n t m u s t b e o b t a i n e d f r o m h i s p a r e n t s . P a r e n t s a r e a u t h o r i z e d t o g i v e p r o x y c o n s e n t , a s t h e y a r e e x p e c t e d t o a c t s o a s t o f u r t h e r t h e b e s t i n t e r e s t o f t h e i r c h i l d . T h e r e f o r e , t h e i r a u t h o r i t y t o g i v e p r o x y c o n s e n t f o r t h e i r c h i l d i s l i m i t e d t o t h e c a s e s w h e r e t h e c h i l d w i l l b e n e f i t f r o m t h e p r o c e d u r e .
Principles 2 . C o n f i d e n t i a l i t y o f M e d i c a l I n f o r m a t i o n T h e g e n e t i c i n f o r m a t i o n o b t a i n e d f r o m t h e g e n e t i c t e s t i s c o n f i d e n t i a l i n f o r m a t i o n o f t h e t e s t e d i n d i v i d u a l . I t s h o u l d b e d i s c l o s e d t o h i m a s l o n g a s h e w a n t s t o b e t o l d . I t m a y b e d i s c l o s e d t o h i s r e l a t i v e s o r f a m i l y m e m b e r s i f h e c o n s e n t s t o i t b e i n g d i s c l o s e d . I t m a y n o t d i s c l o s e d t o t h e m a g a i n s t h i s w i l l .
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