Register for updates

 
 

Medicine & Health
RSS Feed
Lack of Thyroid Hormone Blocks Hearing Development
Monday, September 22, 2014 9:30:00 AM

TAU researchers discover that a genetic form of deafness is due to absence of thyroid hormone


Scanning electron microscopy of inner hair cells from cochleas of wild type (top) and mutant (bottom) mice. Image courtesy Dr. Karen Avraham and Dr. Amiel Dror.

Fatigue, weight gain, chills, hair loss, anxiety, excessive perspiration — these symptoms are a few of the signs that the thyroid gland, which regulates the body's heart rate and plays a crucial role in its metabolism, has gone haywire. Now, new research from Tel Aviv University points to an additional complication caused by thyroid imbalance: congenital deafness.

The study, published in Mammalian Genome, was conducted by Prof. Karen B. Avraham and Dr. Amiel Dror of the Department of Human Molecular Genetics and Biochemistry at TAU's Sackler School of Medicine. Using state-of-the-art imaging, the researchers found that congenital deafness can be caused by an absence of a thyroid hormone during development.

"Since our laboratory mainly focuses on the system of the inner ear, the study of a system such as the thyroid gland was new to us and therefore challenging," said Dr. Dror. "My curiosity as to how these two systems interact together to develop normal hearing led to this multidisciplinary study."

A colorful approach

Prof. Karen Avraham and Dr. Amiel Dror
Dr. Karen Avraham and Dr. Amiel Dror.

The researchers used mouse populations to study a form of congenital deafness that affects humans. Harnessing electron microscopy at the Sackler Cellular & Molecular Imaging Center, researchers tracked the inner hair cells of the cochlea (the auditory portion of the inner ear) in two groups — control (wild) mice and mutant (congenitally deaf) mice. Inner-ear hair bundles in the affected mice were labelled with bright colors to highlight the disorganization of the ear's hair cells.

Examination of the inner ear showed a spectrum of structural and molecular defects consistent with hypothyroidism or disrupted thyroid hormone action. The researchers' analysis of the images revealed defective formation of the mice's thyroid glands: labelled thyroid follicles did not grow or grew incompletely.

"Our work demonstrated that normal hearing fails to develop when thyroid hormone availability is insufficient as a result of a genetic mutation," said Dr. Dror. "Our model provides a platform to test therapeutic approaches in order to prevent hearing loss before it occurs. There is still long way ahead before we get to the point of practical treatments with our research, but we believe we are moving in the right direction."

A lifelong commitment

"My attraction to sound began very early as a child," said Dr. Dror. "I play string instruments and pay great attention to sound quality and perception. As a graduate student in the Avraham laboratory, I was exposed to the fascinating world of genetics and the opportunity to combine two fields of research that I am interested in: genetics and hearing. Now that I have continued this research as a medical student, the direct interaction with patients with hearing impairments encouraged me to explore the clinical significance of my research."

As a physician, Dr. Dror believes it is important to pursue research with clinical consequences for his patients. "The basis of all advanced medicine relies on both basic science and clinical research. I hope that our study will contribute a modest part to global efforts for improved medical care and treatment of hearing impairments," Dr. Dror said.

The study was supported by the National Institutes of Health and I-CORE Gene Regulation in Complex Human Disease.




Latest News

TAU Awards Honorary Doctorate to Oscar®-Winning Producer Steve Tisch

Philanthropist and filmmaker honored for vision and global influence in cinematic arts and for significant investment in university.

Genetic Testing Proves Bene Israel Community in India Has Jewish Roots

TAU–Cornell collaboration provides insight into unique community whose history is largely unknown.

New Study Shows We Are Bad Judges of Friendship

TAU researchers find inability to determine who our real friends are limits our powers of persuasion.

IDEAS Los Angeles Announces New Interactive Features for June Conference

Second annual conference hosted by AFTAU will include an outdoor demo lab, digital graffiti wall, virtual reality immersion and an international DJ.

TAU Student Film Wins Applause at Legendary Tribeca Film Festival

BBC calls Ben Hakim's The Operator "compelling."

Smartphone Users Are Redefining Privacy in Public Spaces

TAU study highlights how smartphone technology is leading to diminished privacy.

IDEAS Los Angeles Conference Announces Initial Speaker Lineup

Second annual conference to unite global industry leaders from Los Angeles, Silicon Valley and Tel Aviv on June 15-16 in Santa Monica.

Handwriting Analysis Provides Clues for Dating of Old Testament Texts

Inscriptions dating to 600 BCE suggest widespread literacy at the time, say TAU researchers.

TAU Uses “Deep Learning” to Assist Overburdened Diagnosticians

Researcher engineers a cutting-edge solution for radiologists and other medical staff.

TAU Study Reveals How Diet Shaped Human Evolution

The Neanderthal rib-cage and pelvis expanded to adapt to a high-protein diet in Ice-Age Europe, researchers say.

Biological Mechanism Passes On Long-term Epigenetic "Memories"

TAU researchers discover the on/off button for inheriting responses to environmental changes.

Cyborg Cardiac Patch May Treat the Diseased Heart

TAU researchers combine electronics with living tissues to create a self-regulating cardiac patch.

Second Annual IDEAS Los Angeles Conference Set for June 2016

AFTAU hosts annual conference uniting global industry leaders from Los Angeles, Silicon Valley and Tel Aviv.

Mutated Gene Associated With Colon Cancer Discovered in 18th-Century Hungarian Mummy

TAU finding suggests genetic predisposition to cancer already existed in pre-modern era.

contentSecondary
c

©2016 American Friends of Tel Aviv University