A gene that mutated half a billion years ago and now shows up in modern sea creatures could hold the key to understanding a rare form of diabetes. The disease, called diabetes insipidus (not to be confused with diabetes mellitus), causes sufferers to urinate more than three-fourths of a gallon every day. An estimated 41,000 U.S. patients suffer from diabetes insipidus.
The high volume of urination in insipidus sufferers is caused by an inability to produce a hormone called vasopressin, which tells the body how much urine to make. According to researchers at Queen Mary’s School of Biological and Chemical Sciences at the University of London in Great Britain, that inability is the result of a mutation in the human gene that controls vasopressin production. A very similar gene that controls the production of “sex proteins” has been discovered in such marine animals as sea urchins.
The sea creatures’ gene produces NG peptides, proteins that allow males and females to release, respectively, their sperm and eggs at the same time, thereby increasing the chances of reproductive success. The British scientists theorize that some five million centuries ago, the gene for vasopressin production mutated and became associated with NG peptide production. The effect, 500 million years later, has been good for sea critters, but not so good for certain land-dwelling mammals
Based on what they’ve learned about the animal gene for NG peptide production, scientists believe that they can better understand the workings of the mutated gene that causes diabetes insipidus. If they can transfer their insights from experiments with sea creature genes to manipulation of the mutated human vasopressin gene, they could take a big step toward treating the disease and mitigating its major symptom.
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