PHP Type 1B is best described as:

PHP Type 1B is best described as:

• A. Disorder of isolated resistance to PTH
• B. Generalized resistance to multiple hormones
• C. Isolated resistance to calcitonin
• D. Resistance to vitamin D metabolism

Answer: (A)

Pseudohypoparathyroidism type I-B is a form of end-organ resistance to parathyroid hormone that is limited to the PTH axis. In this subtype, the kidneys and bones do not respond properly to PTH, causing hypocalcemia and hyperphosphatemia with elevated PTH, but there is typically no resistance to other hormonal pathways or features of Albright hereditary osteodystrophy. The defect is often an imprinting abnormality at the GNAS locus that specifically impairs the renal response to PTH, while other hormone signaling remains intact. So the best description is isolated resistance to PTH.

Pseudohypoparathyroidism type I-B is a form of end-organ resistance to parathyroid hormone that is limited to the PTH axis. In this subtype, the kidneys and bones do not respond properly to PTH, causing hypocalcemia and hyperphosphatemia with elevated PTH, but there is typically no resistance to other hormonal pathways or features of Albright hereditary osteodystrophy. The defect is often an imprinting abnormality at the GNAS locus that specifically impairs the renal response to PTH, while other hormone signaling remains intact. So the best description is isolated resistance to PTH.