by Josh Forman, Head of Science, Education & Outreach
Jnetics aims to screen everyone of Jewish descent so that they have the knowledge of whether they are a carrier of one of the 47 life-shortening and debilitating recessive conditions. Over 1 in 3 people (42%!) with Jewish ancestry (at least 1 Jewish grandparent) are healthy carriers of at least one disorder that Jnetics tests for.
If you know about it, you can do something about it. In a world where so much is in flux and volatile, one major, mind boggling, positive development is the extent and detail to which we can look at our DNA. The insight that this can provide could be one of the most powerful, influential factors possible for a family starting out on its journey. Conditions such as Tay-Sachs, Cystic Fibrosis, Spinal Muscular Atrophy and 44 others can become conditions of the past, in the same way that proactive treatment eradicated smallpox. They’ll never completely disappear, but no one needs to contract and suffer them.
It’s a relatively recent discovery, in reality, that we can look into our DNA. DNA’s structure was worked out in 1953, and the human genome was mapped in 2003. The stories of DNA and the conditions lurking in it start much earlier, and have bubbled along in the background whilst these major milestone breakthrough events occurred, were celebrated and accelerated other learning.
Tay-Sachs, arguably the most well-known disorder that we screen for, and highlighted recently by Courtney Green on TOWIE (The Only Way is Essex) was first identified in 1881 by Warren Tay, a British ophthalmologist who noticed a strange red spot in the retina of a one year old patient with a progressive degeneration of the central nervous system; this red spot is characteristic of a range of related conditions such as Neimann-Pick and Sandhoff diseases. It was then independently identified in 1887 by the neurologist Bernard Sachs in America, noting the cellular changes in particular patients, the heritability of the condition and that it was more common in the Ashkenazi Jewish population.
A new group of chemicals in nervous tissue, later called gangliosides, was characterised in 1935 by Ernst Klenk at the University of Cologne. These molecules, a broad family of ‘gangliosides’, appear across the body in the membranes of nerve cells, and in particular, the central nervous system. We now know that this molecule is important for our cells to interact with each other.
In 1960, Robert Terry and Saul Korey found ‘membranous bodies’ (i.e. bubbles in the nerve cells) filled with a particular type of gangliosides, ‘GM2 gangliosides’ in the neurons of Tay-Sachs patients.
In 1969, Shintaro Okada and John S. O’Brien, researching at the University of California, San Diego, identified the actual gene that causes Tay-Sachs. The gene, HEXA, which sits on Chromosome 15, codes for an enzyme that, along with others, breaks down GM2 ganglioside in the brain. This means that HEXA regulates the amount of the ganglioside present. In Tay-Sachs patients, this control doesn’t happen, so the substance builds up and accumulates to toxic levels destroying the nerve cells of the brain and spinal cord. This leads to the devastating symptoms and premature death of those born with Tay-Sachs.
Why do I discuss this? This gene that does a very specific, seemingly tiny job in the nerve cells of the central nervous system – just regulating a molecule that nerve cells have on their outside, can have devastating impacts when it is faulty.
However, in this world of flux and volatility, the constant, incremental development in scientific and medical understanding over centuries is something to behold and has got us to the amazing place we are now in. This is something to cherish. Something to be proud of in our society and most importantly to utilise to prevent suffering in the future. We are able to identify if you are one of the 1 in 24 people of Ashkenazi Jewish descent that carry a genetic variant in your HEXA gene. With this knowledge, support can be provided with proactive, preventative medical intervention to make sure that their children do not suffer from one of the 47 conditions we screen for.
All we have to do as individuals is a simple cheek swab that takes no more than a minute to complete.
And this is only 1 of the 47 conditions that we screen for.
Please sign up to get screened today, so that you can have the knowledge of what is in your DNA and take action to prevent the potential future suffering of your children with a devastating genetic condition.
