Hutchinson-Gilford Syndrome, more commonly known as progeria, is an extremely rare and progressive disorder that causes affected children to start rapidly aging from the age of 2 years old. The premature aging disorder affects approximately 1 in 4 million to 8 million newborns worldwide. At any given time, around 250 children suffer from Hutchinson-Gilford Syndrome.
Affected individuals may start showing symptoms within the first months of their lives, with the main symptom being a lack of growth or failure to thrive. By the age of 2, other, more prominent symptoms may start to present themselves like diminished growth, alopecia of the entire body, and distinct progeria-associated facial characteristics.
The premature aging seen in progeria is often associated with premature death, with the older ever survivor of progeria being just 29 years old. The cause of death in most cases of progeria is either cardiovascular or cerebrovascular insufficiency.
Pathophysiology of Hutchinson-Gilford Syndrome
The autosomal dominant condition results from new mutations in the LMNA gene that is usually responsible for encoding the protein Lamin A. Normally, this lamin A is responsible for the proper shape of the nuclear membrane as it is a scaffold (supporting) protein. Lamin A is produced by the enzymatic cleavage of prelamin A or progerin protein.
When the LMNA gene is mutated, it results in a decrease in Lamin A production. This occurs due to the mutation of the recognition site on progerin protein required for the enzyme to bind and then cleave it off. This results in the accumulation of prelamin A which causes the nuclear membrane to become unstable, eventually resulting in cell death.
The exact mechanism that leads to cell death from the nuclear envelope disintegration is not known yet.
New drug treatment for Hutchinson-Gilford Syndrome
Most of the treatment options for progeria have been focused on reducing the complications. Apart from supportive therapy, not much could be done in the past for those affected by progeria. However, the US Food and Drug Administration has approved a new drug that targets the progerin protein and helps reduce its accumulation in the body.
The drug Lonafarnib under the brand name Zokinvy by Eiger BioPharmaceuticals, Inc. was approved in November of this year after its efficacy was tested and proved in clinical trials that are ongoing since 2007.
About the Zokinvy Drug
Zokinvy is an oral farnesyltransferase inhibitor that prevents the buildup of progerin in the body. This is especially important because progerin buildup in the heart and blood vessels is the main causative agent for premature death in progeria patients.
In individuals not affected by Hutchinson-Gilford Syndrome, progerin and progerin-like protein accumulation occur over 50 to 60 years, resulting in cardiovascular diseases or stroke in old age. However, in progeria patients, this buildup is ultra accelerated and results in early death, mostly by the average age of 15 years.
Lonafarnib also has anti-neoplastic features and is primarily used for the treatment of certain types of cancers. Moreover, a study performed on twenty-five progeria patients with the specific objective of analyzing neurologic features and benefits of lonafarnib found that there was a significant decrease in episodes of transient ischemic attacks, headaches, and even seizures with the use of lonafarnib.
Lonafarnib also results in weight gain, increased height, and several audiological benefits, all with minimal side effects. It also increases the life span by an average of 2.5 years.
The FDA approval for Zokinvy is the breakthrough in the treatment of progeria that the patients have been waiting for. It has various benefits with very mild side-effects like nausea vomiting, diarrhea, infection, decreased appetite, and fatigue. These are pretty common side-effects and can be treated with supportive therapy.
Other uses for Lonafarnib
Lonafarnib’s mechanism of action makes it a great candidate for use in the treatment of Hutchinson-Gilford Syndrome, progeroid laminopathies, and perhaps, cardiovascular diseases.
Many of the cardiovascular features of Hutchinson-Gilford Syndrome like accelerated atherosclerosis and arteriosclerosis of small vessels is very similar to atherosclerosis and arteriosclerosis of aging usually seen in non-progeria, old-aged individuals.
This similarity indicates that the progerin protein accumulation is at least partly responsible for cardiovascular insults and attacks. Hence, it may be beneficial to use the Zokinvy drug, lonafarnib in non-progeria patients to prevent cardiac attacks and improve the life-span of affected individuals.
Cardiovascular diseases are a major medical and financial burden worldwide with one in every 4 deaths in the United States alone is from cardiovascular disease, which rounds up to approximately 655,000 deaths per year.
More research needs to be done to evaluate if lonafarnib can be used in the cardiac care units, to treat and prevent several cardiovascular diseases from progressing any further.
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A similar concept applies to the use of lonafarnib for the treatment of cerebrovascular diseases and reducing the risk of death from these conditions. Furthermore, neurological disorders like stroke, migraines, or seizures have a significantly negative impact on the quality of life of the patient.
If a drug that already exists on the market has been tested for its safety and efficacy can be used to reduce all of the negative side effects along with the prevalence of neurological disorders, then no time should be wasted and studies should be initiated promptly to further analyze its role, solely, in reducing cerebrovascular diseases prevalence and intensity.
There is a strong possibility that the drug lonafarnib may be beneficial in treating multiple conditions and not just progeria and progeroid laminopathies, the conditions for which it has been approved by the FDA. Further studies need to be performed to assess and evaluate the use of lonafarnib in reducing the intensity and frequency of cardiovascular and cerebrovascular diseases along with the risk of death normally associated with these conditions.