Type 1 Renal Tubular Acidosis (RTA) primarily affects which part of the nephron?

• A. Proximal Convoluted Tubule
• B. Distal Convoluted Tubule
• C. Glomeruli
• D. Collecting Duct

Answer: (B)

Type 1 Renal Tubular Acidosis (RTA), also known as distal RTA, primarily affects the Distal Convoluted Tubule of the nephron. This condition is characterized by the inability of the kidneys to excrete hydrogen ions effectively in this segment, leading to a buildup of acid in the blood, resulting in metabolic acidosis.

In Type 1 RTA, the distal tubule's impairment results in an inability to maintain the normal acid-base balance of the body. While the proximal convoluted tubule does play a role in bicarbonate reabsorption, Type 1 RTA is specifically associated with the distal parts of the nephron where acid secretion occurs. This distinction is crucial for understanding the underlying physiology of the condition and how it can lead to various clinical signs and symptoms, such as bone demineralization and nephrocalcinosis, due to chronic acidosis.

This focus on the distal tubule helps clarify why treatment strategies may involve addressing the acidemia and its consequences, rather than issues predominantly arising from proximal tubular dysfunction.