Question

Both genetic and nongenetic factors cause the congenital skeletal abnormality known as clubfoot, which occurs with a worldwide incidence of about 1 in 1000 births. Gurnett et al. identified a family in which clubfoot occurred as an autosomal dominant trait due to a mutation in the PITXI gene. DNA testing revealed that 47 people in the family carried the PITXI mutation, but only 19 of these people had clubfoot. Calculate the penetrance of the PITXI mutation in this family. Penetrance: (please give your answer in decimal form)

Answer 1

Clubfoot penetrance in the given family with the PITXI mutation is calculated as the number of affected individuals over the total carrying the mutation, resulting in a penetrance of 0.404 or 40.4%.

Step-by-step explanation:

The congenital skeletal abnormality known as clubfoot has both genetic and nongenetic factors contributing to its presence at birth. A family was studied where clubfoot was transmitted as an autosomal dominant trait due to a mutation in the PITXI gene. To calculate the penetrance of this mutation, one must divide the number of people who exhibit the phenotype (those who have clubfoot) by the total number of individuals carrying the mutation. In this case, 19 people have clubfoot out of the 47 who carry the mutation. Therefore, the calculation for penetrance is 19/47 = 0.404. This indicates that the PITXI mutation penetrance in this family is 0.404, or 40.4% when expressed in percentage form.