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Over the last 20 years, researchers have identified a number of genetic variations that can confer an increased risk of developing Parkinson’s. Tiny alterations in regions of DNA (called genes) – which provide the instructions for making a protein – can increase one’s chances of Parkinson’s.
A better understanding of the biological pathways associated with these genetic risk factors is opening up vast new areas of research.
Recently researchers have been exploring the biology behind one particular genetic risk factor – involving a gene called TMEM175 – and they have discovered something quite unexpected: While one genetic variation in the TMEM175 gene increases the risk of Parkinson’s, another variation reduces it.
In today’s post, we will explore the biology of TMEM175, review what the results of the new research indicate, and consider why these findings might be interesting in terms of potential future therapeutic targets.
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Wadlow (back left). Source: Telegraph
Robert Pershing Wadlow was always in the back of school photos.
Born February 22nd 1918, Wadlow’s birth certificate indicated that he was “normal height and weight“, but from that point onwards, there was nothing normal about his rate of growth.
By the time, Robert was 8 years old, he was taller than his father (he was 6 foot/183cm). And eight years later when he turned 16, Robert was 8 foot 1 (2.47 m)… and he was still growing.
Here is a picture of him with his family at 19 years of age:
Robert was the tallest person in recorded history, and at the time of his death – at the tragically young age of 22 – Robert was almost 9 feet tall (8 ft 11; 2.72 m)… and still growing.
His incredible growth was caused by a condition called hyperplasia of his pituitary gland. This condition that results in an overactive pituitary gland which causes an abnormally high level of the human growth hormone to be produced.
Human growth hormone (or somatotropin) is a peptide hormone that belongs to a much larger group of molecules that are referred to as growth factors.
In general terms, growth factors are small molecule that plays an important and fundamental role in biology. They stimulate cell proliferation, wound healing, and occasionally cellular differentiation.
And Robert’s story is an example of how powerful the effect these tiny molecules can have.
Growth factors are secreted from one cell and they float around in the extracellular world until they interact with another cell and initiate survival- and growth-related processes.
We have often discussed growth factors on this website in the past, with posts of growth factors like GDNF (Click here to read a SoPD about this) and CDNF (Click here to read a SoPD post on this). These discussions have largely focused on how growth factors could have neuroprotective and regenerative potential for Parkinson’s, stimulating survival and growth of cells.
Recently, however, new research has been published that demonstrates how some of these growth factors could be influencing an entirely different aspect of cellular biology that is connected to Parkinson’s: lysosomal function.
What is lysosomal function?