Duchenne’s muscular dvstrophy-
**Core Concept**
Duchenne's muscular dystrophy (DMD) is a severe, progressive, and inherited disorder characterized by muscle degeneration and weakness due to a deficiency of dystrophin, a crucial protein essential for muscle function and integrity.
**Why the Correct Answer is Right**
DMD is caused by a mutation in the dystrophin gene, leading to the production of an abnormal or truncated dystrophin protein. This deficiency disrupts the dystrophin-glycoprotein complex, causing muscle fibers to be more susceptible to damage and leading to progressive muscle degeneration. The absence of dystrophin also affects the muscle's ability to regenerate, contributing to the disease's relentless progression.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not accurately describe the primary cause of Duchenne's muscular dystrophy.
**Option B:** This option is incorrect as it mentions Becker's muscular dystrophy, a milder form of the disease caused by different mutations in the dystrophin gene.
**Option C:** This option is incorrect as it mentions a different type of muscular dystrophy, such as myotonic dystrophy or limb-girdle muscular dystrophy, which have distinct pathophysiological mechanisms.
**Clinical Pearl / High-Yield Fact**
DMD is an X-linked recessive disorder, primarily affecting males, as they have only one X chromosome. Female carriers, who have one normal and one mutated X chromosome, may exhibit mild symptoms or remain asymptomatic.
**Correct Answer:** C.