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Genetics

06 April 2018

The disorder that makes it impossible for a 3-year-old boy to eat

Aaron Lipschitz (3) is the only person in SA suffering from a rare immune disease. We take a look at this condition.

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Recently a three-year-old boy, Aaron Lipschitz, made headlines in South Africa. He is currently the only child in the country diagnosed with an extremely rare disorder called Interleukin-12 Receptor defect. Aaron’s immune system is ineffective, which means that he is unable to fight common infections.

But what exactly is the disease that causes this dire effect?

The boy who can’t eat

As a result of this disorder, Aaron has been battling with salmonella infection, a common food-borne illness, for nearly two years. When he was one year old, he survived septicaemia, caused by the salmonella infection. He was one of the 0.1% of babies who are allergic to breast milk protein and couldn’t consume any other food item, formula or liquid, apart from water.

Aaron has never been able to tolerate food and is currently dependent on an intravenous feeding port at night to keep him alive. He has only been able to drink a specialised hypoallergenic formula called Neocate for the last three years and requires a bottle of this formula every two hours during the day to keep him hydrated and nourished.

Aaron is also highly allergic to most medications and even has a negative reaction when he touches some materials. 

What is Interleukin-12 Receptor defect?

Interleukin-12 Receptor defect is a rare, incurable disorder that affects the immune system. The Interleukin-12 Receptor in the human body is responsible for activating the immune system. When this receptor is impaired, such as in Aaron’s case, the body can no longer fight minor infections.

Up until now, fewer than 300 people worldwide have been reported with Interleukin-12 Receptor defect. Among these cases, only three have reportedly developed autoimmunity, helping them ward off infections.

What causes Interleukin-12 Receptor effect?

According to an article published in Clinical Infectious Diseases, Interleukin-12 receptor defect is caused by a large deletion or mutation of the gene responsible for regulating the immune system. The condition is often inherited.

What are the possible signs and symptoms?

Children with Interleukin-12 Receptor defect often present with infections that can't be warded off by their natural immune system. This leads to recurring bouts of various illnesses such as pneumonia, arthritis, skin infections, sepsis, high fever and other conditions that can be life-threatening.

In a number of recent cases there weren't any symptoms or unusual infections until bacteria such as salmonella were contracted – after which symptoms kept on reoccurring.

The first case of this rare disorder was identified in 2003.

How is Interleukin-12 Receptor defect diagnosed?

The first patient identified with Interleukin-12 Receptor defect had recurrent bouts of salmonella despite various courses of antibiotics over 18 months, while blood tests revealed no abnormalities. When the patient's blood cells were further tested, it however revealed an impaired cellular response, indicating this genetic defect.

In cases of recurrent infections, doctors need to do genetic testing to determine whether this defect is present.

What are the treatment options?

While there is currently no treatment for Aaron’s disorder, the only possible treatment option would be extensive chemotherapy to destroy his entire existing immune system – to be rebuilt by a bone marrow transplant

While doctors are unsure about the outcome of this procedure, they are hoping that it would enable Aaron to tolerate food. 

Other treatment options have been researched, but none delivered the desired outcome. An article published in the Journal of Immunology explored treatment with a type of protein called cytokine, but the optimal dose needed for successful treatment couldn't be determined.

Image credit: iStock