[Mathematical approach to the differential diagnosis of phenotypically similar hereditary diseases].

The paper, which is based on the report made at XIV International Genetical Congress, concerns the problems of applying mathematical methods in differential diagnosis of relatively rare hereditary diseases (Marfan's disease, homocystinuria, mucopolysaccharidosis, epiphyseal dysplasias) and in analysis of phenotypical differences in dominant and recessive type of inheritance. Results of algorithmic mechanisms of detection, which provide a diagnosis during establishment of phenotypically homogeneous subgroups of patients within existing nosologic entities, are discussed. With such an approach, efficiency of diagnosis reaches 90% and more. In case of various possible modes of inheriting a disease with a genealogic history fragmentary or absent the authors propose that determining a possible type of hereditary transmission should be approached by analysis of phenotypical similarity of difference with reference to patients with cleared dominant or recessive type of inheritance. The latter is based on the discovery of phenotypical difference between patients with differing types of transmission of the mutant genes.