Researchers at the Cairo University Pediatric Hospital, in Egypt and at the Baylor Research Institute in Dallas conducted a study on Egyptian patients with the genetic Gaucher disease (GD) type 3 and found that those patients have clinical outcomes that are very different from type 3 patients in other countries.
The study, “Long-term follow-up and sudden unexpected death in Gaucher disease type 3 in Egypt,” was published in Neurology Genetics.
GD is caused by mutations in the GBA gene that greatly reduce or eliminate the activity of the enzyme beta-glucocerebrosidase, leading to the toxic accumulation of substances that damage several tissues and organs.
Three types of GC exist.
Type 1 GD, the most common form of the condition, does not affect the brain and spinal cord, and thus is called non-neuronopathic GD. It is characterized by enlargement of the liver and spleen, reduced number of red blood cells, easy bruising due to decreased platelets, lung disease, and bone abnormalities.
Type 2 and 3 GD are neuronopathic forms of the disease known to affect the central nervous system in addition to type 1 symptoms. Patients experience abnormal eye movements, seizures, and brain damage.
Type 3 GD, which worsens at a slower rate than Type 2 GD, is observed in about 5% of all GD patients in the U.S and Europe, but recent reports indicate that Type 3 GD is more prevalent in China, Korea, and Egypt.
To understand the neurological history of type 3 GD, the researchers analyzed 78 Egyptian patients with the disease and followed them from one to 9 years.
Because systemic symptoms characteristic of all types of GD are known to affect the neurologic outcome of patients, the researchers only enrolled patients who were on long-term enzyme replacement therapy (ERT). With ERT, beta-glucocerebrosidase is administered to reduce the disease systemic effects, with no reported effects on the neurological effects of the disease. Long-term ERT allowed them to study the intrinsic neurologic natural history of Gaucher disease type 3.
Results revealed that patients from the cohort exhibited marked behavioral abnormalities, abnormal eye movements, seizures, and sudden unexpected death associated with epilepsy or an isolated seizure. The clinical observations were different and particularly more severe than that of other populations with type 3 GD, but the reason behind the differences remain unknown.
Although epilepsy could be used to explain sudden death, researchers noted that the cohort of Egyptian Type 3 GD patients had a much higher incidence of sudden death than other epilepsy populations. They suggest that controlling seizures might be the best way to prevent sudden death.
Researchers concluded that a need exists for the identification of genes altered in this ethnic group that might be responsible for the different clinical outcomes. Identifying the genes may lead to the development of new therapies for neuropathic GD that could benefit all GD patients.