Single-gene DisordersSingle-gene Disorders

Classification ofClassification of genetic disorders genetic disorders

Single-gene disorders (2%)Chromosome disorders (<1%)Multifactorial disorders (60%)

PedigreePedigree

PedigreePedigree

PedigreePedigree

PedigreePedigree symbols symbols

Types of MutationTypes of Mutation

class of mutation

mechanism frequency examples

Genome chromosome missegregation

10-2 / cell

division

aneuploidy

Chromosome chromosome rearrangement

10-4 / cell

division

trans-locations

Gene base-pair mutation

10-10 / cell

division

point mutations

Gene MutationGene Mutationbase-pair mutationbase-pair mutation

Nucleotide Substitutions(point mutations)

DeletionsInsertions

Gene MutationGene Mutationbase-pair mutationbase-pair mutation

Nucleotide Substitutions (point mutations) silent mutationsmissense mutations (amino acid substitutions)

nonsense mutations (premature stop codons)

RNA processing mutationsRegulatory mutations

Gene MutationGene Mutationbase-pair mutationbase-pair mutation

Deletions and Insertions small number of bases

is not a multiple of 3, cause frameshift is a multiple of 3, cause loss or gain of codons

larger gene deletions, inversions, fusionsinsertion of L1 or Alu element dynamic mutations – triplet expansion

Genetic disorders with classical Genetic disorders with classical Mendelian inheritanceMendelian inheritance

Dominant Recessive

Autosomal Autosomal dominant

Autosomal recessive

X-linked X-linked dominant

X-linked recessive

Autosomal dominant traitAutosomal dominant trait

Autosomal dominant pedigreeAutosomal dominant pedigree

Huntington’s diseaseHuntington’s disease

Huntington’s diseaseHuntington’s disease

Huntington’s diseaseHuntington’s disease

Huntington’s diseaseHuntington’s disease

Autosomal recessive traitAutosomal recessive trait

Autosomal recessive pedigreeAutosomal recessive pedigree

Cystic fibrosisCystic fibrosis

Cystic fibrosisCystic fibrosis

Cystic fibrosisCystic fibrosis

X-linked recessive traitX-linked recessive trait

X-linked recessive traitX-linked recessive trait

X-linked recessive pedigreeX-linked recessive pedigree

HemophiliaHemophilia

HemophiliaHemophilia

HemophiliaHemophilia

LiteratureLiterature

Biology, eighth edition,Campbell, Reece

Unit three: GeneticsChapter 14: Mendel and the Gene IdeaConcept 14.4: Many human traits follow

Mendelian patterns of inheritancePages 276 – 279