In: Biology
Question 15 - Cystic fibrosis is transmitted as a(n):
X-linked recessive gene |
|
autosomal recessive gene |
|
autosomal dominant gene |
|
chromosomal defect |
Cystic fibrosis is an autosomal recessive disorder. This disorder occurs because of the mutation in CFTR gene. Normally CFTR gene instructs to make protein called cystic fibrosis transmembrane conductance regulator. This channel protein helps to transport Cl- ions in and out of the cell, which helps the water movement in tissue necessary for production of thin, freely flowing mucus. This mucus helps to lubricate and protect the lining of different systems like digestive, organs as well as air passage. It also regulates the transport of positively charged ions like Na+ across the cell membrane.
mutation in CFTR gene leads to deformation of CFTR protein,
leading to mucus build up, which persistently leads to infection
inside the body ( e.g., lung infection).
Cystic fibrosis is an
autosomal recessive disorder means the CFTR gene is
located on an autosome ( other than sex chromosome.) . That's why
it is not X linked or Y linked. This genetic condition appears when
individual receives two copies of defective autosomal CFTR gene. So
the condition recessive. If a child has cystic fibrosis , that
means he is homozygous for cystic fibrosis disorder.