The EconomistMarch 14th 2020 Technology Quarterly |Personalised medicine 3N
eena nizaris 42 years old, a professor of business studies and
just 122cm tall. The ends of her bones are soft and pliable: on
an x-ray they look frayed, like old paintbrushes. During her child-
hood and adolescence in Dubai she was operated on 30 times. The
source of her problem remained a mystery. In 2010, after three de-
cades of wondering, she finally received a diagnosis: Jansen’s
Metaphyseal Chondrodysplasia, a condition first recognised in
the 1930s. Her problems stem from a broken copy of just one of her
20,000 genes.
Dr Nizar is in some ways very unusual. Fewer than one in 200m
people have the mutation to thePTH1Rgene that causes Jansen’s
disease. In other ways she is like everyone else. Although few peo-
ple have a defect as debilitating, everyone’s health, and ill-health,
is tied to the contents of their genomes. All genomes contain ar-
rangements of genes that make psychological disorders, cancers,
dementias or circulatory diseases either more of a problem or less
of one. Everyone has genes that make them better or worse at me-
tabolising drugs, more or less likely to benefit from specific forms
of exercise, better able to digest some foods than others.
The same arrangement will never be seen twice. Though for
identical twins the differences are the height of subtlety, each of
the 7.5bn human genomes sharing the planet is unique. That irre-
ducible diversity represents a challenge to many of the 20th cen-
tury’s greatest medical advances, which were based on a one-size-
fits-all approach. Personalising medicine is an enticing opportu-
nity for improvement.Good doctors have always treated their patients as individuals.
In the 20th century blood tests,x-rays, body scans and other diag-
nostic tools made the specifics of each patient’s particular pro-
blems ever more visible. A spectacular reduction in the cost of
reading, or sequencing, thedna“bases” that make up human ge-
netic information is adding a new level of individuality. It is now
possible to inspect genetic differences with an ease previously un-
imaginable, and thus to know something about propensities to
disease well before any symptoms show up.
Nobody knows exactly how many human genomes have been
fully sequenced, and different sequencing procedures read the ge-
nome to different degrees—there are quick skims and painstaking
philological studies. But the number is in the millions (see chart
overleaf ). By the 2030s genome sequencing is likely to be as rou-
tine in some places as taking a pin-prick of blood from a baby’s
heel is today—it may even be part of the same procedure. Genome
science is becoming a matter of practical medicine. New therapies
that make it possible to adjust or edit this genetic inheritance are
coming to market.
This flood of data is allowing medicine to become more precise
and more personal—in many ways, the p-words are two sides of
the same coin. Previously recognised genetic diseases, such as
Jansen’s, have been traced to specific genes and can be connected
to defects in the proteins they create (almost all genes describe
proteins, and proteins do almost all the body’s chemical work).
Most of these diseases are rare, in that they typically affect no morePopulations of one
Medicine is getting to grips with the fact that everyone is an individual, says Natasha LoderPersonalised medicine1