fabry disease in canada: an overview of stats, symptoms and treatments
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fabry disease, a rare inherited genetic condition, affects roughly one out of every 40,000 males, with females being affected at twice that rate. the exact prevalence of fabry disease in canada isn’t known, but various estimates put the numbers around 500 people in canada.
according to medline plus, the prevalence rates of fabry disease globally sit between 1 in 1000 and 1 in 9000 people, with milder forms of the disease accounting for more cases. with the steep variations in numbers, it’s hard to determine the exact numbers of the disease both globally and nationally.
due to the sheer rarity of fabry disease, clinical research regarding its prevalence in canada is severely limited. current studies surrounding fabry disease focus more on management, outcomes and clinical characteristics.
what is fabry disease?
fabry disease is considered a genetic lysosomal storage disorder, a group of inherited metabolic disorders that develop when the body doesn’t produce enough enzymes to break down toxic materials in the cells, leading to a buildup of these materials within the body.
the disease is caused by genetic mutations of galactosidase alpha (gla) genes that inhibit the production of the enzyme needed to break down fatty substances. in fabry disease specifically, the enzyme required to break down fats is limited, leading to higher fat storage within the body, mainly collecting in tissues and blood vessels.
this enzyme, alpha-galactosidase a (alpha-gal), breaks down a fat-like substance known as sphingolipids. the gene is inherited on the x chromosome from parents in different ways. if a father has the gene mutation, they will pass it on to every daughter they have, who can then pass it on to their children.
since sons inherit y chromosomes from their fathers, they are not at risk of the gene being handed down to them if their father has it. if a mother has the gene, they can pass it on to both their daughters and sons at a rate of 50%.
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when a person inherits fabry disease and has the mutated gene, the lipids build up in the body, leading to dangerous health consequences, including:
- heart attacks
- arrhythmias
- enlarged heart
- heart failure
- kidney failure
- nerve damage
- strokes and transient ischemic attacks (tia, mini-strokes)
there are two types of fabry disease, characterized by the time of symptom onset. they include:
- classic
- late-onset/atypical
classic fabry disease develops in childhood or adolescence with mild symptoms that worsen over time. atypical fabry disease develops in people over 30 and is typically discovered after a person is hospitalized due to kidney failure or heart disease.
out of the two types, atypical is more common, affecting roughly 1 in every 1500 to 4000 males as opposed to the 1 in 40,000 males affected by the classic type. the incidence rates of fabry disease in females aren’t well known because females often lack the same telltale signs of the disease, or their symptoms are so mild they don’t notice they have them.
when symptoms do develop, they can include:
- feelings of numbness, tingling, burning or pain in the feet or hands
- extreme levels of pain during physical activity
- intolerance to heat or cold
- abnormal eye patterns, known as cornea verticillate
- dizziness
- fatigue, fever, and body-aches that resemble the flu
- gastrointestinal distress, such as constipation, abdominal pain, and diarrhea
- tinnitus, or ringing in the ears
- hearing loss
- proteinuria, or high levels of protein in the urine
- angiokeratoma, which are dark skin lesions that appear on the chest, back, and genital area
- hypohydrosis or anhidrosis, which are little to no sweating, respectively
- edema, which is swelling in the legs, ankles, or feet
to get a definitive diagnosis of fabry disease, people must undergo various tests, including:
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- an enzyme assay designed to measure levels of the alpha-gal enzyme
- genetic testing to check for the gla gene mutation
- screenings in newborns
since fabry disease is complex and rare, treatments are limited and typically revolve around introducing a synthetic version of the alpha-gal enzyme into the body to restore proper levels or undergoing oral chaperone therapy, which works by repairing alpha-gal enzymes within the body to help foster proper function and the breakdown of fatty substances.
fabry disease survival and treatments in canada
since there is no cure for fabry disease, treatment is the only option available for people with the faulty gene. in canada, the two mainstay therapies are mentioned above: enzyme replacement therapy and oral chaperone therapy. that said, some promising emerging therapies could help those with fabry disease in the near future. they include:
- substrate reduction therapy (srt)
- gene therapy
srt is an oral molecule drug that stops the biosynthesis of glycosphingolipids in the body. it’s designed to prevent the production of a substrate that encourages the accumulation of fats in the body. the second, gene therapy, involves introducing new genetic material into the body to fight off the disease.
with a lack of viable treatment options, people with fabry disease are often left to cope and deal with symptoms even while in active therapy. oral therapy using the drug migalastat, which was only approved for use in the late 2010s, is shown to be effective in just under half of people with fabry disease.
in people who receive ert, the odds of an improved quality of life are poorly understood. some clinical studies have seen marked improvement after ert with regression of heart disease, namely left ventricular hypertrophy. in contrast, other studies only show a small or no improvement with ert. others have even seen a worsening of the disease, with the walls of the heart thickening gradually over time with ert.
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people with fabry disease are often plagued with a lower quality of life and lower life expectancy than the general population. on average, males with fabry live a total of 58 years and females a total of 75 years, compared to the general population of 75 and 80 years for males and females, respectively. due to limited canadian data, these numbers were pulled from the fabry disease news site, which is based in the united states.
many factors go into average life expectancies for people with fabry disease, such as when they were diagnosed, the age at which their symptoms started, and when treatment began. according to research, the most common cause of death in people with fabry disease is cardiovascular disease at a rate of 53.6 per cent in males and 50 per cent in females. other common causes in males include:
- cerebrovascular disease
- renal disease
- infections (sepsis, septicemia, pneumonia)
in females, the second most common cause of death was cancer at a rate of 30 per cent. it’s important to note that the study in question had a small sample size and, thus, may not reflect the overall numbers of larger groups of people with fabry disease.
current fabry disease statistics in canada
the current statistics surrounding fabry disease in canada are scarce due to a lack of research and the sheer rarity of the disease. according to the canadian fabry disease initiative, roughly 469 people in the country have been diagnosed with fabry disease, with the majority residing in nova scotia.
while other studies citing the prevalence rates are severely limited, it’s suggested that numbers of people who have the disease are underestimated. there may be more people living with fabry disease than previously thought or documented. previous estimates place the worldwide prevalence at 1 in 117,000 people.
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the currently available research on fabry disease in canada centers around symptoms, treatment viability, and other factors that do not play into the prevalence of the rare disease. one study examined the connection between fabry disease and cryptogenic ischemic stroke (is) and found that 0.3 per cent of young patients who experienced is were found also to have fabry disease.
when looking at the most common complications experienced by canadians with fabry disease, research shows that 42 per cent of people will have cardiac complications, and 38 per cent will experience renal complications. this is further confirmation of u.s.-based studies on fabry complications.
the future of fabry disease in canada
while the future of fabry disease in canada is unclear due to a lack of clinical research and treatments, awareness surrounding the disease and its effects on those who have it will continue to aid in more significant pushes toward finding viable therapies that work for more patients, alongside more research to help diagnose people with fabry who may go undiagnosed for more extended periods of time.
since the symptoms of the disease can appear in many other metabolic disorders, it can be hard to determine if someone has fabry unless proper testing is done. the canadian fabry disease initiative aims to improve several approaches to fabry disease in the country by collecting outcomes data from canadians living with the disease. this will help to establish data registries regarding treatment options, as well as diagnostic processes.
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