CHROMOSOMAL MUTATIONS AND ASSOCIATED HEREDITARY DISEASES: ETIOLOGY AND PATHOGENESIS

This article provides a comprehensive analysis of the etiology and pathogenesis of hereditary diseases caused by chromosomal mutations. Changes in chromosome number and structure — aneuploidy (trisomy, monosomy), polyploidy, deletion, duplication, translocation, inversion, and complex “de novo” structural variants (dnSVs) — lead to severe developmental defects in early embryogenesis, pregnancy loss, and congenital multisystem disorders. The article thoroughly examines etiological aspects such as meiotic nondisjunction, premature sister chromatid separation (PSSC), reverse segregation, weakening of cohesin and spindle apparatus, the effect of advanced maternal age, environmental mutagens, and genetic factors (including the high frequency of consanguineous marriages in Central Asia). It also proposes strategies for prenatal screening, genetic counseling, and disease prevention.