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Forum Name: Endocrinology Topics
Question: Vasopressin Mystery?
|AMH61805 - Sun Aug 01, 2010 7:17 pm||
My 22mth old daughter was being tested for DI, because she was always thirsty, and uriniating large amounts. She had the water deprivation test. Throughout the test, her nephrologist was very pleased with the results he was getting, and said he was 99% sure that everything was fine, and she definitely didn't have DI. However, the full report will be back in 3-4wks.
I recieved a call that just like the nephrologist stated before, her urine and blood was concentrated like it should be, BUT somehow her vasopressin levels were almost non-exsistent. They should be normal as well. I was told that the renal team will be conversing with the endocrinology team, and getting back to me, since this is "perplexing."
My question is, how could her concentration be so normal, if there was no vasopressin? What is helping her concentrate? Is this a sign there is something wrong with her pitituary or hypothalmus? (excuse the spelling)
I know the doctors will explain things to me, but I hate going in blind, and I need something to go on here! Any help would be appreciated! Thank you!
|Dr.M.jagesh kamath - Fri Aug 13, 2010 11:38 am||
Hello,Why the child has passed the water deprivation test despite deficient in AVP(ArginineVasoPressin)?Obviously there must be some vasopressin like substance.In condition(Which is very rare)Autosomal Recessive Familial Diabetes Insipidus the parentsare normal to water deprivation.The child remains aysmptomatic for the first year with no normal AVP. But there is a compensatory response from a mutated hormone Leu-AVP.Measured with radioimmunoassay the levels were increased 30 times normal,thereby suggesting that unknown mechanisms might partially compensate the deficiency of AVP in very young children.
(Ref-Human Molecular Genetics Volume 8, Number 7 Pp. 1303-1307)- Autosomal Recessive Familial Neurohypophyseal Diabetes Insipidus with Continued Secretion of Mutant Weakly Active Vasopressin.
Michael D. Willcutts, Eric Felner and Perrin C. White+
Division of Pediatric Endocrinology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75235-9063, USA
Hope this information is useful in your discussions.Best wishes.
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