Answer to Question #175839 in Genetics for tima

Question

Achondroplasia, a form of Hereditary Dwarfism ( 10 points)

Achondroplasia is a hereditary constitutional bone disorder; it is the most common type of dwarfism, in which the child’s arms and legs are short in proportion to body length and have a characteristic face . This disease is caused by a mutation of the fibroblast growth factor receptor-3 gene (FGFR3) on human chromosome 4.

 Document 1 : A pedigree of a family whose certain members are affected by Achondroplasia.

1- Indicate if the allele responsible for the disease is dominant or recessive. Justify the answer.

2- Determine the chromosomal localization of the gene responsible for Achondroplasia .

3- Specify the genotype of each of the individuals (I-1), (III-9), and (IV- 4).

Homozygous fetuses that possess two copies of the mutant gene are not viable, and pregnancy is naturally interrupted.

4- Determine the risk for the couple III- 9 and III- 10 to have a third child affected by Achondroplasia.

Answer 1

1: Dominant. The gene is inherited meaning that one parent must have the trait.

2: It is expressed in tissues such as cartilage, brain, intestines and kidney.

3:Ff

ff

Ff

4: The risk is that the pregnancy will be naturally interrupted.