Mendelian Inheritance Patterns

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Terms in this set (43)
Autosomal Dominant diseaserare, heterozygotes rarely have children, new mutations happen. One heterozygote and one homozygous normalFitnessthe number of offspring that reach reproductive age divided by the average number for the populationAutosomal Recessive Diseaseonly the homozygous carriers show symptoms. Normal occurrence is that patients are offspring of two heterozygous carriers. New mutations are rareHaplionsufficiencyone copy delivers insufficient amount of productAutosomal dominant inheritancephenotype shows presence of allele also in heterozygote; gene on autosome (not x or y)Autosomal recessive inheritancephenotype only present when two bad alleles are presentHow to recognize autosomal recessive inheritanceaffected do not normally have affected parents; average of 1/4 affected in each sibship; the parents are often related at some distantHow to recognize autosomal dominant inheritanceall affected have an (one) affected parent (except new mutations and reduced penetrance); average of 50% affected in a sibshipHow to recognize autosomal inheritanceEqual number of affected males and femalesHypophosphatemiarickets, misshaped, bent weight-bearing bones. x-linked inheritancex-linked recessivephenotype if there is no other allele present. hemizygous males is common, homozygous female is very rareX-linked dominantalways show phenotypeY-linked inheritancemale fertility; reports of non-syndromic hearing impairmentHow to recognize x-linked recessive inheritancemany more males than females affected; never father to son transmission, new mutations happen, affected nephew-uncle pairs: more common than in autosomal recessiveHow to recognize x-linked dominant inheritancemore females than males affected; never father-to-son transmissionHow to recognize Y-linked inheritanceonly father-to-son transmission1/2 of sons are affected; 1/2 of daughters are carriersmother is heterozygous with a X-linked recessive inheritance1/2 of sones are affected; 1/2 of daughters are affectedmother is heterozygous with a X-linked dominant inheritanceall daughters are carriers; no sons are carriersFather is affected with a X-linked recessive inheritanceAll daughters are affected, no sons are carriersFather is affected with X-linked dominant inheritanceSex-limited inheritancetypically influences traits expressed in one sex only or traits influenced by the sex hormonesReduced Penetrancecharacteristic of a disease. Person is completely without signs or symptomsNon-penetrant personone who has the predisposing genotype but does not show symptomsVariable expressivitydifference in severity or in age of onset for seemingly identical genotypeMitochondrial Inheritancefrom female carrier to all of her offspring, from male carrier to no-onelocus heterogeneitycaused by involvement of different loci= different genes, symptoms should be identicalAllelic heterogeneitycaused by different alleles at the same locus = same gene. Symptoms may be same or differentPhenocopieslooks like a known genetic disorder, but is caused by environmental influencePleiotrophymutaiton is one gene has more than one effect, effects in more than one physiological systemContiguous gene disorderstypically deletion or duplication of part of a chromosomeExample of Phenocopyholt-oram syndromeexample of pleiotrophycystic fibrosisexample of contiguous gene disordersDiGeorge syndrome