New cause of inherited heart condition discovered

Date:
September 24, 2021
Source:
University College London
Summary:
The discovery provides a new causal explanation for 1-2% of adults
with the condition.



FULL STORY ==========================================================================
A UCL-led research team has identified a new gene as a cause of
hypertrophic cardiomyopathy, an inherited heart condition affecting one
in 500 people.


==========================================================================
The discovery, published in the European Heart Journal, provides a new
causal explanation for 1-2% of adults with the condition. (In the UK,
this is approx.

1,250-2,500 people.) As a result of the study, the new causal variants,
known as truncating ALPK3 (alpha-protein kinase) variants, should be
added to genetic testing/screening, allowing doctors to identify a
greater number of people who are at risk of developing the condition
and who would therefore benefit from regular monitoring.

In hypertrophic cardiomyopathy, heart muscles are thicker, which can make
it harder for the heart to receive and pump blood. While in most cases
the condition will not affect daily life, it can cause heart failure
and is frequently cited as the most common cause of sudden unexpected
death in young people.

About half of cases already have known genetic causes, linked to eight
to 10 specific genes (only two of these single genes were found in the
last decade).

Lead author Dr Luis Lopes (UCL Institute of Cardiovascular Science), also
a Consultant Cardiologist at Barts Health NHS Trust, said: "Hypertrophic cardiomyopathy is an extremely common genetic condition. Earlier,
small-scale studies suggested that variants in the ALPK3 gene could be
a cause of a rare paediatric form of cardiomyopathy, but only when two
abnormal copies were inherited. We have now proved that just one abnormal
copy is enough to cause hypertrophic cardiomyopathy in adults, looking
at a large number of patients and families. This form of inheritance
(autosomal dominant) is much more prevalent, as inheriting just one
abnormal copy of a gene is more likely than inheriting two.



========================================================================== "Identifying a new genetic cause is important as it opens up new
possibilities for potential treatment. It also helps families who have
been affected by the condition, but who did not know why, to know that
a cause has been found for their specific case." In the new study, an international team of researchers analysed the genomes of 2,817 people
with hypertrophic cardiomyopathy referred from centres in Spain, the
UK, Denmark, Russia, Latvia, Brazil, and Argentina. They compared the prevalence of the ALPK3 variants with that of the general population,
finding it was 16 times more common.

Researchers also studied the presence of the variant within families,
testing whether or not it was causal by looking at whether the variant
tracked with disease -- that is, whether family members who had the
variant also had the disease.

The research team looked at the distinct nature of the disease compared
to when it was caused by faults in the sarcomere genes -- the primary
way the disease is inherited. (They are named the sarcomere genes as
their function relates to sarcomeres, the basic contractile unit, or
primary building block, of muscle fibre.) They found that, in cases
where the new gene is implicated, the disease was diagnosed later (at
an average age of 56) but had similar rates of heart failure and heart transplantation as in cases linked to sarcomere genes.

While little is known about the functional consequences of ALPK3 variants,
they are believed to play a role in the regulation of protein function
through a process of phosphorylation. Proteins are fundamental to the
process of heart muscle cells contracting and relaxing.

Dr Lopes said: "ALPK3 variants represent a different pathway to the
disease than the other main known causes in the sarcomere genes. This
discovery is exciting as it will establish new targets for therapies. We
now need to explore mechanisms that explain how the ALPK3 variants are
linked to the condition." In the UK, genetic testing is offered to all
those diagnosed with hypertrophic cardiomyopathy in referral centres
such as Barts Heart Centre, and, if there is a known genetic cause,
to family members as well. While there is at the moment no cure, people
with the condition are monitored regularly, medicated and one important intervention is the fitting of an implantable cardioverter defibrillators (ICD), a device similar to a pacemaker that can give a strong electric
shock to the heart if it detects a dangerously abnormal heartbeat.

The study received funding from the Medical Research Council and the
British Heart Foundation.

========================================================================== Story Source: Materials provided by University_College_London. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Luis R Lopes, Soledad Garcia-Herna'ndez, Massimiliano Lorenzini,
Marta
Futema, Olga Chumakova, Dmitry Zateyshchikov, Maria Isidoro-Garcia,
Eduardo Villacorta, Luis Escobar-Lopez, Pablo Garcia-Pavia, Raquel
Bilbao, David Dobarro, Maria Sandin-Fuentes, Claudio Catalli,
Blanca Gener Querol, Ainhoa Mezcua, Jose Garcia Pinilla, Torsten
Bloch Rasmussen, Ana Ferreira-Aguar, Pablo Revilla-Marti', Maria
Teresa Basurte Elorz, Alicia Bautista Paves, Juan Ramon Gimeno,
Ana Virginia Figueroa, Raul Franco-Gutierrez, Maria Eugenia
Fuentes-Can~amero, Marina Martinez Moreno, Martin Ortiz-Genga,
Jesus Piqueras-Flores, Karina Analia Ramos, Ainars Rudzitis, Luis
Ruiz-Guerrero, Ricardo Stein, Mayte Triguero- Bochara'n, Luis de
la Higuera, Juan Pablo Ochoa, Dad Abu-Bonsrah, Cecilia Y T Kwok,
Jacob B Smith, Enzo R Porrello, Mohammed M Akhtar, Joanna Jager,
Michael Ashworth, Petros Syrris, David A Elliott, Lorenzo Monserrat,
Perry M Elliott. Alpha-protein kinase 3 (ALPK3) truncating variants
are a cause of autosomal dominant hypertrophic cardiomyopathy.

European Heart Journal, 2021; 42 (32): 3063 DOI: 10.1093/eurheartj/
ehab424 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/09/210924104257.htm

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