Human Genetics - 2019

Not all diseases and disabilities are caused by genes. And there can be a false positive
where someone presents with symptoms but does not have a corresponding genetic
defect as well as a false negative where someone has a genetic defect but does not
present with symptoms. Worse, different versions of a gene can cause wildly
different symptoms. For example, from the SAITO application software
SAITO - genes in different categories
As can be seen above, the ABCD4 gene (a real gene found on chromosome 14 in
the q24.3 region) is associated with at least three seemingly unrelated conditions -
see the red rectangle. In a similar manner, the CD40 gene (found on chromosome
20 in the q13.12 region) is associated with three apparently unrelated conditions
- see the blue rectangle. Things are rarely simple - Graves Disease is part of a
spectrum and there are at least eight genes involved in it. Likewise, rheumatoid
arthritis is a spectrum of symptoms with at least 52 different genes involved.
If you are are a parent, a physician or the person getting a DNA test that shows that
your INS, ABCD4 or CD40 gene is faulty is not sufficient - what is necessary to know
is what is the specific defect or the specific defects. A major difficulty is that genetic
research continues - new effects of genes are found so that what the Human Genome
Project thought was normal or functional in 2003 no longer is. That means vendors
who provide DNA sequencing need an on-going national or, preferably,
planetary standard for what is a functional sequence, what is not and what is unclear.
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