A Case of a Novel Mutant Vasopressin Receptor-Dependent Nephrogenic Diabetes Insipidus With Bilateral Non-Obstructive Hydronephrosis in a Middle Aged Man
|Title:||A Case of a Novel Mutant Vasopressin Receptor-Dependent Nephrogenic Diabetes Insipidus With Bilateral Non-Obstructive Hydronephrosis in a Middle Aged Man|
|Authors:||Miyakoshi, Masashi; Kamoi, MD, Kyuzi; Uchida, Shinichi; Sasaki, Sei|
|Date Published:||December 01, 2003|
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This translation by the NDI Foundation is to assist the lay reader. To provide a clear, accessible interpretation of the original article, we eliminated or simplified some technical detail and complicated scientific language. We concentrated our translation on those aspects of the article dealing directly with NDI. The NDI Foundation thanks the researchers for their work toward understanding and more effectively treating this disorder.
© Copyright NDI Foundation 2007 (JC)
His history suggested the possibility of NDI. To see if the causal mutation was either in the AQP2 gene or the V2R gene, the researchers injected the patient with DDAVP, a synthetic analogue of the hormone, arginine vasopressin (AVP). They then measured the patient?s response to this outside the kidney. Specifically, they measured the patient?s heart rate, diastolic blood pressure, facial flushing, and the amount of cAMP in the blood and urine. If there are changes in these parameters, the NDI is caused by a mutation in the AQP2 gene: if there are no changes, the NDI is caused by a mutation in the V2R gene.
The patient?s NDI was caused by a mutation in his V2R gene that produced a structural change in a portion of the V2R protein called the first extracellular loop. This is only the second time this particular mutation has been reported in the literature, and the researchers speculate that the two patients expressing these mutations may have had common ancestors. Finally, this type's mutation may not trigger a serious acute outcome but rather slowly progressive disease.