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This medical video lecture of sqadia.com expansively elaborates the family history and pedigree analysis. Various terminologies have been discussed in this lecture. Determination of linkage relationships and mode of inheritance can be done through pedigrees. Furthermore, product rule and consanguinity has also been highlighted. Interpretation of collected data and clinical correlations between the genetic disorders have been delineated.
Background and Systems Integration
In this section, the educator explained about the pedigree which is a series of Mendelian crosses involving relatives that can yield significant clues about a genetic disorder. Modern studies now utilize the DNA markers like short tandem repeats (STRs) or hypervariable mutations. Pedigrees are organized by generations. Propositus and proposita are the terminologies employed for males and females, respectively. Basic pedigree analysis includes assuming answers to the questions and determination of the mode of inheritance of that disorder. In addition to that, linkage relationships can also be determined via pedigree analysis.
Sample Pedigree Evaluation
Determination of mode of transmission of genetic disorder allows for the characterization of a trait. The genetic defect can either be transmitted in a dominant or recessive pattern. The product rule is applied to the probabilities. This rule describes that the likelihood of two or more events to occur simultaneously equals the product of their individual probabilities. It assists in the pedigree analysis and calculates the probabilities of unknown events. Family history holds significance in medical record. Incident of any disorder running in the family can range from high to moderate and low.
Family relationships pedigrees have been delineated in this section. These are the graphical representations of members of kindred. Determination of degree of relationship can be mathematically defined and is the coefficient of relationship. Third generation pedigree can be carried out for paediatric patients or even for adults. Obtaining family history for any genetic malady ought to be determined. Consanguinity is the mating of the two closely related individuals. It demonstrates alternative relationships like adoption, half-siblings etc. The ethics call for the maintenance of confidentiality of the information.
Interpretation of Collected Data
This section explains comprehensively about the interpretation of the collected data. Interpretation of family history holds its significance. There must be up-to-date three generational pedigrees and pedigree scans. Red flags must also be indicated. These are the affected individual in the family. Moreover, the degree of relationship must also be determined. Simple Mendelian inheritance demonstrates the monogenic etiology. Responding to the family history is also quite important. The presence of positive family history should be followed by counselling of individual, specific tests and certain preventative strategies.
Clinical correlations have been highlighted in this section. Pedigree analysis can indicate the need to modify care. Analysis of any pedigree encompasses the answers to few questions. These can be determining the condition of the individual, intervention strategy which can be opted for, and many more. The trait can either be inherited in a dominant or recessive pattern. Family history of the person needs to be obtained and a pedigree can be constructed from that information. The existence of certain medical conditions like cerebral palsy call for the radiography of the individual as well.