According to recent research, many cases of corticotropin-independent macronodular adrenal hyperplasia appear to result from two copies of a mutant gene. This rare adrenal disorder is one of many causes of Cushing’s syndrome.
A research team comprised of scientists in France and the U.S. National Institutes of Health found that about one-third of a group of patients with corticotropin-independent macronodular adrenal hyperplasia had mutations in both copies of a gene called ARMC5.
One copy of ARMC5 occurred in all the patients’ cells, and the second copy was found only in the cells of the patients’ adrenal tumors.
Most of the family members with only copy of the mutant gene had not developed corticotropin-independent macronodular adrenal hyperplasia and did not have Cushing’s syndrome.
Researchers concluded that it is necessary to have two copies have the mutant gene to develop corticotropin-independent macronodular adrenal hyperplasia.
The first mutation is believed to arise before birth in all cells, and the second mutation is believed to arise later in life specifically in the adrenal gland. It is not clear why the second mutation develops, and why the tumors appear in the adrenal glands alone.
The research team believes that screening family members for the ARMC5 gene, monitoring their cortisol levels, and initiating treatment after the first sign of Cushing’s syndrome can help avoid the long-term complications of the disorder.
The study results are published in the New England Journal of Medicine.
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