Morphan’s syndrome is as a result of

The correct option is Pleiotropic gene.

Step-by-step Explanation:

1. Understanding Marfan Syndrome:
Marfan syndrome (often misspelled as Morphan's syndrome in the question) is a genetic disorder of the connective tissue. It is caused by mutations in the FBN1 gene, which encodes the protein fibrillin-1. Fibrillin-1 is essential for the proper formation of extracellular matrix and elastic fibers in various tissues throughout the body.

2. Defining Pleiotropy:
Pleiotropy is a genetic phenomenon where a mutation in a single gene influences multiple, seemingly unrelated phenotypic traits or organ systems. In the case of Marfan syndrome, a single mutation in the FBN1 gene leads to a wide range of clinical features affecting different parts of the body, including:
- Skeletal system: Long, slender limbs, tall stature, and chest wall deformities.
- Ocular system: Dislocation of the lens of the eye (ectopia lentis) and severe nearsightedness.
- Cardiovascular system: Weakening of the aorta, which can lead to aortic aneurysm or dissection.

3. Analyzing the Options:
- Pleiotropic gene: Since a single gene mutation results in multiple distinct physical effects across the skeletal, cardiovascular, and ocular systems, Marfan syndrome is a classic example of pleiotropy.
- Polygene: Polygenic inheritance involves multiple genes contributing to a single phenotypic trait (e.g., skin color or height), which is the opposite of pleiotropy.
- Pseudogene: These are non-functional segments of DNA that resemble functional genes but do not code for proteins.
- Modifier gene: These are genes that alter the phenotypic expression of another gene, rather than directly causing the primary disease phenotype on their own.

Therefore, Marfan (Morphan's) syndrome is caused by a Pleiotropic gene.