Gamstorp Disease: Symptoms, Causes, Treatments, Risk Factors

Gamstorp disease is also known as HYPP or HyperKPP or Hyperkalemic periodic paralysis and it is an inherited autosomal dominant disorder affecting the sodium channels in our muscle cells and the ability to regulate the levels of potassium in the blood. Gamstorp disease is actually a rare condition that is characterized by muscle weakness or hyperexcitability which is exacerbated by potassium, cold or heat, and it can lead to uncontrolled shaking that is followed by paralysis.

Gamstorp disease is an inherited disease and it is possible for individuals to carry and to pass on the affected gene without ever experiencing any symptoms. It is found that 1 in 250, 000 people suffer with this rare condition.⁽¹⁾

Usually the onset of this disease occurs in early childhood, but this occurs even with adults. So, gamstorp disease causes episodes of severe muscle weakness, with attacks that often begin in the childhood.⁽²⁾

Let’s check more about the condition in the following sections.

One of the most common symptoms of gamstorp disease is paralysis. Patients suffer from paralytic episodes that are short and might end in a few minutes. However, there might be longer episodes too that might run for 2 hours.

These paralytic episodes usually begin all of a sudden. So, you might not find a safe place to wait out an episode and you might experience injuries from falls, which are quite common in this case.

Generally paralytic episodes start in infancy or during early childhood. Most people experience the paralytic episodes in a more frequent manner that increases through their adolescent years and into their mid 20s. However, as one approaches 30s, the attacks gets less frequent and for some patients, they even disappear altogether.

One more symptom of gamstorp disease is myotonia. Here, some of your muscle groups can become rigid temporarily and it might get difficult for you to move. This can be really very painful. But, some individuals do not feel any sort of discomfort during an episode.

Because of constant contractions, the affected muscles usually look well-defined and strong; however, you might find that you can only exert little or no force using these affected muscles.

This symptom or myotonia can result in permanent damage in several cases. Some patients with gamstorp disease might have to use wheelchairs eventually due to deterioration of their leg muscles.

Right treatment in the right time can generally prevent or can reverse progressive muscle weakness.

There are also some other symptoms of gamstorp disease and they are irregular heartbeats, severe weakness of limbs, skipped heartbeats, stiffness of muscles, immobility and permanent weakness.

This condition is caused because of a mutation, or alteration, in a gene known as SCN4A. This is the gene that helps in producing sodium channels, or the microscopic opening through which sodium gets to move through cells.

Electrical currents that are produced by different potassium and sodium molecules passing via cell membranes control our muscle movements.

In case of gamstorp disease, these channels have some sort of physical abnormalities and that leads to the potassium to gather on one side of the cell membrane and start building up in the blood. This in turn prevents the required electrical current from forming and eventually causes you to become unable to move your affected muscle.

This disease is an inherited disease and it is autosomal dominant; which means that you only require having one copy of the mutated gene so as to develop gamstorp disease.

We must also mention that you have 50% of chance having this mutated gene in you if any one of your parents is a carrier. However, some individuals who have the gene never ever develop symptoms of the disease.

In order to go for any sort of treatment for gamstorp disease we first need to diagnose the condition. For diagnosing the disease, your doctor would first rule out adrenal disorders like Addison’s disease. Your doctor will also try to rule out genetic kidney diseases that can result in abnormal levels of potassium. After this, the doctor will be able to confirm if it is gamstorp disease through some blood tests, DNA analysis, or by checking your serum electrolyte and potassium levels.

For evaluating these serum electrolyte and potassium levels, you might have to undergo some tests that would involve moderate exercise followed by rest so as to see how your potassium levels change.

Now, once your condition is properly diagnosed your treatment would begin. Treatments for gamstorp disease generally depend on the severity and also the frequency of your episodes. Medications and supplements work quite well for lots of people suffering from this disease. For others, avoiding specific triggers work really well.

Most individuals have to depend on their medications for controlling paralytic attacks. Acetazolamide or Diamox is one of the most commonly prescribed medicine, which is also commonly used for controlling seizures.

You might also be prescribed with diuretics by your doctor so as to limit the levels of potassium in the blood.

If you are suffering from symptoms of myotonia, you might be treated by using lower doses of medicines, such as Mexiletine( Mexitil) or Paroxetine (Paxil); which would help in stabilizing severe muscle spasms.

If you are experiencing mild symptoms in gamstorp disease you can try some home remedies. You can add mineral supplements, like calcium gluconate to any sweet beverage so as to stop a mild episode.

Moreover, drinking one glass of tonic water or simply sucking a piece of hard candy at the first signs of a paralytic episode might also help you.

You might not prevent Gamstorp disease as it is hereditary; however, you can moderate the effects of the disease by simply managing your risk factors quite carefully.

You should talk to your doctor if you are experiencing frequent episodes or if you have severe paralytic attacks or other symptoms that might be due to gamstorp disease.

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