Navigation Links
New cause of thyroid hormone deficiency discovered
Date:11/12/2012

International researchers, including a team at McGill University, have discovered a new cause for thyroid hormone deficiency, or hypothyroidism. This common endocrine disorder is typically caused by problems of the thyroid gland, and more rarely, by defects in the brain or the pituitary gland (hypophysis). However, a new cause of the disease has been discovered from an unsuspected source and is reported in the journal Nature Genetics. The scientists, led by McGill Professor Daniel Bernard, Department of Pharmacology and Therapeutics in the Faculty of Medicine, identified a new hereditary form of hypothyroidism that is more prevalent in males than in females. This sex bias shone a light on where to look for the underlying cause.

"Our collaborators in the Netherlands had been following a family in which two cousins had an unusual syndrome of hypothyroidisim and enlarged testicles," said Prof. Bernard. "Using state-of-the-art DNA sequencing technologies, we identified a mutation in a gene called immunoglobulin superfamily, member 1 (IGSF1), in both boys and their maternal grandfather. As one of few labs in the world studying this gene, we initiated a collaboration to determine whether the observed mutation might cause the disorder. At the time, the IGSF1 gene was known to be active in the pituitary gland, but its function was a mystery".

"Shortly after, we were contacted independently by a second group of researchers, studying a second family, in which two young brothers suffered from hypothyroidism and also harbored a mutation in the IGSF1 gene, though it was a different mutation than that observed in the Dutch family," said Prof. Bernard, "The fact that there were two unrelated families with the same male-biased clinical syndrome and mutations in the same gene strongly suggested that the mutations played a causal role in hypothyroidism".

The groups reached out to researchers in the Netherlands, the UK, Italy and Australia who were following similar families and found that affected males all had mutations in their IGSF1 gene. Overall, the team identified 11 families with 10 different mutations in IGSF1.

"We went on to show that mutations in IGSF1 block the protein it encodes from moving to the cell surface, where it normally functions", explained Beata Bak, McGill Ph.D. student and the paper's co-first author. "We also observed that the pituitary glands of mice lacking IGSF1 had reduced levels of the receptor for a brain-derived hormone known as thyrotropin-releasing hormone (TRH). If we think of TRH as a key, then its receptor is the lock into which the key fits to produce its effects. Our results suggest that in the absence of IGSF1, the pituitary gland becomes less sensitive to the brain's instructions to secrete thyroid-stimulating hormone (TSH). As a result, the thyroid gland receives a reduced impetus to produce thyroid hormones".

The group's findings are significant as IGSF1 mutations cause a variable, though principally mild, form of hypothyroidism that would likely escape detection by most perinatal thyroid function screening methodologies. In addition, since the IGSF1 gene is highly polymorphic, there may be many individuals (boys and men, in particular) in the general population with presently undetected, but clinically significant hypothyroidism.

Symptoms of the disease include fatigue, weight gain, cold sensitivity, and muscle weakness. If left untreated, hypothyroidism increases the risk of developing heart disease. In infants, hypothyroidism can cause neurodevelopmental delay and, in extreme circumstances, cretinism.

"A simple test could identify carriers of IGSF1 gene mutations or variants who might benefit from thyroid hormone replacement therapy. Our results highlight a fundamental role for this protein in how the brain and pituitary gland control thyroid function and therefore the whole body metabolism. We hope our work will inspire new research on IGSF1's function in the pituitary gland under various physiological and pathophysiological conditions", said Prof. Bernard.


'/>"/>

Contact: Chris Chipello
christopher.chipello@mcgill.ca
514-398-4201
McGill University
Source:Eurekalert

Related biology news :

1. Will a genetic mutation cause trouble? Ask Spliceman
2. Record-breaking grant: New research project to investigate the causes of mental disorders
3. BPA could affect reproductive capabilities, cause infection of the uterus
4. Researcher who identifed genetic cause and possible treatment for Marfan syndrome honored
5. A new gene thought to be the cause in early-onset forms of Alzheimers disease
6. Long-term research reveals causes and consequences of environmental change
7. Changes in brains blood flow could cause brain freeze
8. Yeast cell reaction to Zoloft suggests alternative cause, drug target for depression
9. Glycogen accumulation in neurons causes brain damage and shortens the lives of flies and mice
10. Double the pain: RUB biologists find the cause of pain in the treatment of fair skin cancer
11. Gene mutations cause massive brain asymmetry
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/5/2017)... KEY FINDINGS The global market ... CAGR of 25.76% during the forecast period of 2017-2025. ... for the growth of the stem cell market. ... MARKET INSIGHTS The global stem cell market is segmented ... The stem cell market of the product is segmented ...
(Date:4/3/2017)... , April 3, 2017  Data ... precision engineering platform, detected a statistically significant ... product prior to treatment and objective response ... the potential to predict whether cancer patients ... to treatment, as well as to improve ...
(Date:3/30/2017)... , March 30, 2017 The research team ... for three-dimensional (3D) fingerprint identification by adopting ground breaking 3D fingerprint ... new realm of speed and accuracy for use in identification, crime ... affordable cost. ... A ...
Breaking Biology News(10 mins):
(Date:10/11/2017)... ... October 11, 2017 , ... At its national ... Dr. Suneel I. Sheikh, the co-founder, CEO and chief research scientist of Minnesota-based ... selected for membership in ARCS Alumni Hall of Fame . ASTER Labs ...
(Date:10/11/2017)... (PRWEB) , ... October 11, 2017 , ... ComplianceOnline’s Medical ... place on 7th and 8th June 2018 in San Francisco, CA. The Summit brings ... well as several distinguished CEOs, board directors and government officials from around the world ...
(Date:10/11/2017)... the Netherlands and LAGUNA HILLS, Calif. ... The Institute of Cancer Research, London ... use MMprofilerâ„¢ with SKY92, SkylineDx,s prognostic tool to risk-stratify patients ... trial known as MUK nine . The University of ... trial, which is partly funded by Myeloma UK, and ICR ...
(Date:10/11/2017)... ... October 11, 2017 , ... Singh Biotechnology today ... designation to SBT-100, its novel anti-STAT3 (Signal Transducer and Activator of Transcription 3) ... able to cross the cell membrane and bind intracellular STAT3 and inhibit its ...
Breaking Biology Technology: