The importance of the genealogic tree or pedigree build and study in genetic counseling - case report
© Tomulescu et al.; licensee BioMed Central Ltd. 2008
- Published: 17 April 2008
- Public Health
- Genetic Counseling
- Genetic Basis
- Down Syndrome
- Important Application
Determination of the genetic basis of a character from the kinds of crosses we have considered requires the production of large numbers of offspring from the matting of selected parents. The analysis of segregation by this method is not possible in humans, whose matings canat be controlled and is not usually economically feasible for some traits in large domestic animals. However, the mode of inheritance of a trait can sometimes be determined by examining the segregation of alleles in several generations of related individuals. This is especially done with a family tree that shows the phenotype of each individual. Such a diagram is called pedigree or genealogic tree. An important application of probability in genetics is its use in pedigree analysis, a stage in genetic counseling.
To realise a pedigree of an individual or a family, it's a necessity to gather data about the family or individual. We studied a very interesting case in which are involved four individuals with Down syndrome.
We presented a genealogical tree of J.family. One of the member of this family asked genetic counseling. We observed that she had a secondary cousin (a girl) with Down syndrome, and two cousins (men) who have children with Down syndrome, and a cousin (female) who has a child with this syndrome. We demonstrated after genetic counseling with all the phases involved, that in this family the Down syndrome has occurred because of the propensity to 21 chromosomes non-disjunction. The studied case it isn't in danger to have a child with Down syndrome because the genetic propensity is from the ant (wife of father's cousin).
To realise a pedigree of an individual or a family, it's a necessity to gather data about the family or individual. The data about family are systematized in pedigree or genealogic tree of the family. Analysing the pedigree of a family, we can say that some traits are inherited or not. Also, we can anticipate some normal or abnormal traits of individuals of the next generation. The studied case it isn't in danger to have a child with Down syndrome because the genetic propensity to 21 chromosomes non-disjunction is from the ant (wife of father's cousin).
This article is published under license to BioMed Central Ltd.