1.04 - Inherited Disorders

Question 1

What is an allele?

Answer 1

An allele is one of two or more multiple versions of a gene

Question 2

Describe the genetics of Cystic Fibrosis

Answer 2

Autosomal recessive. Mutation in the CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) gene. Most common mutation is the deltaF508. Loss of phenylalanine at the 508 position in the gene.

Question 3

Describe the genetics of Huntington’s Disease

Answer 3

Autosomal Dominant. Extra CAG repeats in huntington gene (HTT) on chromosome 4. The more repeats the more severe the disease.

Question 4

What is genetic anticipation?

Answer 4

The symptoms of a genetic disorder become more apparent and more severe at an earlier age in each subsequent presentation of the disease.

Question 5

What is and provide and example of Co-dominant Inheritance

Answer 5

Co-dominance occurs when the contributions of both alleles are visible in the phenotype. An example is ABO blood grouping. A & B are co-dominant (RBC will have both A & B antigens) while O is recessive.

Question 6

Define: Concordance

Answer 6

When twins develop the same trait

Question 7

Which type of twins have a higher concordance rate?

Answer 7

Monozygotic have a higher concordance rate than dizygotic twins

Question 8

What is Heritability?

Answer 8

Heritability measures the fraction of phenotype variability that can be attributed to genetic variation.

Question 9

Describe the genetics of Haemophilia A

Answer 9

X-Linked recessive. A deletion mutation of a gene involved with blood clotting (Factor VIII). Carriers can show symptoms (bruise easier).