Genetic terms

omranalzobaidi's version from 2015-12-08 16:15


Question Answer
Variable expressivityPhenotype varies among individuals with same genotype( NF in 2 pats very in the degree)
Incomplete penetrate Not all with a mutant genotype show the mutant phenotype( BRCA do not always result in breast or ovarian cancer )
PleiotropyOne gene contribute to multiple phenotypic effects ( CF , OI , PKU )
Loss of heterozygosityIf a pt inherits or develops a mutation in a tumor suppressor gene, the complementary allele must be deleted / mutated before cancer develops . This is not true of oncogenes .
Linkage disequilibriumTendency for certain allele at 2 linked loci to occur together more often expected by chance , measures in population not families
Locus heterogeneityMutation at different loci can produce a similar phenotype( Albinism ) ( Marafan & Ehlers danlos)
Allelic heterogeneityDifferent mutations in the same locus produce the same phenotype ( beta thalassemia )
HeteroplasmyMitochondrial inherited disease
Mosaicism somaticMutation propagates through multiple tissue or organs
Mosaicism GonadalMutation only in egg or sperm