**Question:** All are true about nephronophthisis except:

A. Nephronophthisis is a genetic disorder.
B. It is a rare condition affecting only 1 in 100,000 individuals.
C. It primarily affects children and adolescents.
D. It is caused by infections or environmental factors.

**Core Concept:** Nephronophthisis (NP) is a group of rare genetic disorders characterized by the degeneration of nephrons, which are the functional units of the kidney responsible for filtering blood and maintaining electrolyte and fluid balance. These disorders primarily affect children and adolescents, and are caused by genetic mutations.

**Why the Correct Answer is Right:** Nephronophthisis is indeed a genetic disorder, so options D is incorrect because it suggests that NP is caused by infections or environmental factors. However, the other options (A, B, and C) are true statements about nephronophthisis:

**Why Option A is Incorrect:** Nephronophthisis is a genetic disorder, not caused by infections or environmental factors. Inheritance patterns include autosomal recessive, autosomal dominant, or X-linked recessive, depending on the specific genetic mutation involved.

**Why Option B is Incorrect:** Nephronophthisis is a rare condition affecting approximately 1 in 15,000 to 1 in 100,000 individuals. However, option B specifically states that it affects only 1 in 100,000 individuals, making it incorrect.

**Why Option C is Incorrect:** Nephronophthisis is not limited to a specific age group, but typically begins in childhood or adolescence. However, the statement "It is a rare condition affecting only children and adolescents" is more precise and accurate, making option C incorrect.

**Why Option D is Incorrect:** Nephronophthisis is not caused by infections or environmental factors; it has a genetic basis. The statement "It is not a genetic condition" makes option D incorrect.

**Why Option E is Correct:** Option E, "Nephronophthisis primarily affects children and adolescents," is a correct statement as it highlights the age group typically affected by this genetic disorder.

**Why Option F is Incorrect:** Nephronophthisis is a genetic disorder caused by mutations in various genes, not related to infections or environmental factors. Option F incorrectly suggests that it is caused by infections.

**Why Option G is Incorrect:** Nephronophthisis is a genetic disorder caused by mutations in various genes, not related to infections or environmental factors. Option G incorrectly suggests that it is caused by infections.

**Why Option H is Correct:** Option H, "Nephronophthisis is a genetic condition with mutations in specific genes," accurately reflects the genetic basis of nephronophthisis.

**Why Option I is Incorrect:** Nephronophthisis is a genetic condition caused by mutations in specific genes, not related to infections or environmental factors. Option I incorrectly suggests that it is caused by infections.

**Core Concept:**