Germline Defects Flashcards
Who is affected by X-linked recessive disorders?
Only males
What is the genotype of affected X-linked recessive individuals?
Hemizygous for abnormal allele
What expression is seen in heterzygous females for an X-linked recessive condition?
Variable expression due to random X-inactivation which produces a mosaic
How can females be affected by an X-linked recessive condition?
Due to non-random X inactivation
Who is affected by X-linked dominant disorders?
- Hemizygous males
- Heterozygous females
What is the Hardy-Weinberg principle?
Allele and genotype frequencies in a population remain constant from generation to generation unless specific disturbing influences are introduced
What are disturbing influences in the Hardy-Weinberg principle?
- non-random mating
- mutations
- selection
- random genetic drift
- gene flow
Give 3 examples of monogenic disorders
- Cystic Fibrosis
- Duchenne muscular dystrophy
- Huntingdon disease
Why kind of monogenix disorder is cystic fibrosis?
Autosomal recessive
What protein is mutated in cystic fibrosis?
Transmembrane chloride channel protein
What kind of monogenic disorder is duchenne muscular dystrophy?
X-linked recessive
What gene is mutated in duchenne musclar dystrophy?
Gene for dystrophin which links actin to protein complex in plasma membrane, linking cytoskeleton of muscles
What kind of monogenic disorder is Huntingdon’s disease?
Autosomal dominant
What protein is mutated in Huntingdon’s disease?
Huntingdin
What are trinucleotide repeat disorders?
Involve (XYZ)n sequence with n being increased in affected individuals
