Medical Genetics - V. M. Zaporozhan 2005

Clinical-Genealogical Method
Significance of the Method. Principles of Pedigree Construction
Genealogical Analysis and Genetic Risk Calculation

Stage III: genealogical analysis. The first question to address when analyzing a pedigree is whether the trait is of a hereditary nature; the second is whether the disorder results from a de novo mutation or is inherited, and what the mode of inheritance is in the given family. When analyzing pedigrees, it is necessary to rule out non-paternity, keep in mind the Selection/32.html">Genetic heterogeneity of Hereditary diseases, and account for the existence of phenocopies (non-hereditary conditions that mimic hereditary ones in their symptoms).

Stage IV: genetic risk calculation. Once the inheritance pattern is established, the genotypes of family members are determined, and the magnitude of the genetic risk of having an affected child for the advisees is calculated (Fig. 4.2). Pedigree analysis helps identify individuals at risk who are in need of Genetic Counseling. This allows for planning a comprehensive set of preventive measures to prevent the recurrence of the disease in the family.

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Fig. 4.2. Determining family members' genotypes from the pedigree:

a — pedigree for Autosomal Recessive Inheritance; b — possible genotypes of family members



Last update: 11/08/2026

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