The study of genetics and aHUS

Article No. 319

14 February 2020

The study of genetics really began over 150 years ago when an Augustine Monk called Johann Mendel developed a theory about biological inheritance having studied pea plants!

Francis Crick and James Watson

Decades passed and the science developed. It established a  faster pace when something called “deoxyribunueclitec acid” or “DNA” was thought to be significant. This was confirmed when Francis Crick and James Watson at the University of Cambridge described a model of the double helix that formed DNA.

DNA double helix

DNA had been discovered as the way instructions are given to determine the development ,  functioning ,growth and reproduction of most living things.

DNA sequence

Some more years passed and a scientist called  Fredrick Sanger developed a way to sequence genes. The familiar pictures of intermittent black lines down four columns are synonymous with DNA. His method became the standard for more than 40 years until “Next -Gen” became the more modern alternative. But even now geneticists still prefer to use Sanger to confirm the completeness of new methodology’s results.
Over that period the technological development of the equipment used to undertake genetic test also developed to allow more ubiquitous testing laboratories producing test result at ever reducing costs. In 20 years the cost of genome sequencing has fallen from $100k to $1k.
During the 1990s and completed in 2003, The Human Genome Project (HGP) was an international collaborative scientific project which aimed to determine of the base pairs that make up DNA in humans  and of identifying and mapping all of the  genes of the human genome for their structure and what they do.
Finally a new profession has emerged  to counsel the recipients of results on their personal genetic testing
The first genetic test , which identified a rare genetic variant of significance and  which could be the cause of aHUS , was perfomed 23 years ago. It was directed at one defect in  components of  Complement  and foundone  in Complement Factor H (CFH).
Over the years since  then hundreds of significant variants have been discovered , not just in CFH , but in  other components of Complement. Significant genetic variants have also be discovered in other parts of the blood, e.g the coagulation system, which hamper Complement’s ability to work as it should.
Such genetic research helped the development of eculizumab and its translation to become  an effective treatment for aHUS.
Knowing the disease predisposing genetic variant is important for confirming an aHUS diagnosis, but it also helps to predict how treatment can impact on the outcome of an aHuS onset.
It is also be of use for others in the family of an aHUS patient ,who are themselves unaffected by aHUS to date, but who might, or might not be, “at risk carriers” of the same genetic faults , making them susceptible to aHUS.
The science is in place and can only get better but there also is a challenge for  people to understand and come to terms with the possibilities that the study of genetics offers?

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