Liability,易患性 A concept used in disorders which are multifactorially determined to take into account all possible causative factors
Liability易患性 • A concept used in disorders which are multifactorially determined to take into account all possible causative factors
Threshold High Liability Low Liability Carey et al: Medical Genetics, 4th Edition Copynight o 2010 by Mosby, an imprint of Elsevier, Inc. All rights reserved
Familial aggregation: Affected individuals tend to cluster in families. prevalence of the disease in a relative“r” of an affected person 入r= population prevalence of the disease The higher the familial aggregation the larger theλr Ifnr=l, then the relative is at no greater risk than anyone in the general population
Familial aggregation: Affected individuals tend to cluster in families. prevalence of the disease in a relative “r” of an affected person lr= --------------------------------------------------- population prevalence of the disease • The higher the familial aggregation, the larger the lr . • If lr = 1, then the relative is at no greater risk than anyone in the general population
Twin studies suffer from many limitations Monozygotic(Mz) twins are genetically identical clones and should always be concordant(both the same) for any genetically determined character. Dizygotic dz twins share half their f genes on average, the same as any pair of sibs
Twin studies suffer from many limitations • Monozygotic (MZ) twins are genetically identical clones and should always be concordant (both the same) for any genetically determined character. • Dizygotic (DZ) twins share half their genes on average, the same as any pair of sibs
Carey et al: Medical Genetics, 4th Edition Copyright 2010 by Mosby, an imprint of Elsevier, Inc. All rights reserved