Fanconi’s syndrome is caused by-
**Core Concept**
Fanconi's syndrome is a rare genetic disorder characterized by a defect in the proximal tubules of the kidneys, leading to impaired reabsorption of glucose, amino acids, phosphate, and bicarbonate. This results in excessive loss of these substances in the urine, causing various metabolic disturbances.
**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of Fanconi's syndrome, which involves a defect in the reabsorption of glucose, amino acids, phosphate, and bicarbonate in the proximal tubules. This defect is often due to mutations in the genes encoding for proteins involved in the reabsorption process, such as glucose transporter 2 (GLUT2) or sodium-phosphate cotransporter 2a (NaPi2a). The impaired reabsorption of these substances leads to their excessive loss in the urine, causing hypophosphatemia, hypokalemia, and metabolic acidosis.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the underlying defect in the reabsorption process. While aminoglycosides can cause renal damage, they are not the primary cause of Fanconi's syndrome.
**Option B:** This option is incorrect because it is a consequence of Fanconi's syndrome, not the cause. Hypophosphatemia is a common feature of the disorder, but it is not the underlying defect that leads to its development.
**Option C:** This option is incorrect because it is a general term that encompasses various forms of renal damage, but it does not specifically refer to the defect in the proximal tubules that characterizes Fanconi's syndrome.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that Fanconi's syndrome can be caused by various genetic mutations, including those affecting the sodium-phosphate cotransporter 2a (NaPi2a) gene. This knowledge can help in diagnosing and managing patients with this disorder.
**Correct Answer:** D. **Fanconi's syndrome is caused by a defect in the proximal tubules of the kidneys, often due to genetic mutations affecting proteins involved in the reabsorption process.**