《医学遗传学》7年制课件Multifactorial Disease.ppt

3．Inheritance Traits of MF Disease 0.025(×5) 0.006(×3) 0.007(×7) 2nd degree 0.0075(×1.5) 0.004(×2) 0.003(×3) 3rd degree 0.05(×10) 0.05(×25) 0.04(×40) 1st degree 0.15(×30) 0.40(×200) 0.40(×400) MZ 0.005 0.002 0.001 General Pyloric stenosis Cong. Disloc. of Hip Cleft lip Onset risk Consanguineous marriage also increases the probability of an affected child for a multifactorial trait. 3．Inheritance Traits of MF Disease 3.4．Consanguineous marriage Multifactorial Disease Medical Genetics Qualitative trait Quantitative trait Characteristics of Polygenic Inheritance Threshold Theory Heritability Estimate of Heritability Inheritance Characteristics of Polygenic Disease Estimate of Recurrence Risk Emphasis Polygenic inheritance Multifactorial inheritance (MF) Multifactorial traits (complex disease) are those which result from an interaction between multiple genes and multiple environmental factors.? Polygenic inheritance Multifactorial inheritance (MF) Major gene Minor gene Additive gene Additive effect Codominance Independent Assortment Monogenic trait 1．Characteristics of MF 1.1．Qualitative Trait 120 cm 165 cm aa AA or Aa Height of pituitary dwarfism normal Monogenic trait 1．Characteristics of MF 1.1．Qualitative Trait 0~5% 45%~50% 100% aa Aa AA PAH activity of PKU, carrier normal Monogenic trait 1．Characteristics of MF 1.1．Qualitative Trait Genetic traits which are present or absent. One has the trait or not. Polygenic trait 1．Characteristics of MF 1.2．Quantitative Trait Genetic traits which are measurable characteristics. 1．Characteristics of MF 1.2．Quantitative Trait Polygenic trait 1．Characteristics of MF 1.2．Quantitative Trait 130 140 150 160 170 180 190 200 Height (cm) 80 70 60 50 40 30 20 10 Variability Gaussian distribution the bell-shaped curve 1．Characteristics of MF 1.2．Quantitati