Autism and Cancer

Let me start off by saying this: I have found no research or data that indicates your loved one with Autism is more likely to be diagnosed with cancer because of their Autism. I want you to absolutely understand that because cancer is a scary word. Autism is scary enough on its own and as you have been reading through my blog posts, there is a lot of stuff to know about it, so let’s not compound the Autism stress with scary words like cancer. I, personally, have lost three family members to cancer; cancer runs in my family, and to be quite honest I just don't like this disease.

So why post about it? Because there is a lot of information out there pertaining to a link between certain genetic codes, Autism, and cancer. Certain types of cancer are found to be more prevalence among individuals on the Autism spectrum and I think it’s important for you to know this exists.

The New York Times published an inflammatory and confusing article on this very topic basically stating that Autism has a link to cancer genes. I'm not going to spend much time on it. I prefer the USA Today article published in 2013 on this very topic. According to his article, researchers found in 10% of children with Autism have a mutation of the PTEN gene. This gene is linked to a number of cancers like breast, thyroid, and colon cancer. Autism is also found in approximately half of children diagnosed with tuberous sclerosis. This genetic disorder raises the risk of brain and kidney cancer. Researchers say that a very small proportion of individuals with Autism have PTEN mutations. Scientists have been able to genetically alter mice, with PTEN mutations, to mimic Autism symptoms. These animal studies had prompted a human clinical trial in which a drug is given to children who have Autism and the beginning stages of tuberous sclerosis mutation, scientists hope to wrap up this study later this year, in December 2014. I wouldn't expect to see an official publication of findings until 2015.

What is tuberous sclerosis? The Tuberous Sclerosis Alliance defines tuberous sclerosis (TSC) as a genetic disorder which causes non-malignant tumors in different organs, primarily the brain, eyes, heart, kidney, skin, and lungs. Approximately 1 in every 6,000 births and about 1 million people worldwide have TSC. The cause is either genetic or spontaneous. There are two types of TSC: TSC1- shows on chromosome 9 and TSC2- affects genes on chromosome 16. To understand more about genetics, please read blog series Understanding Genetics. 

TSC of skin

Forbes magazine published an outstanding article in 2013, also about Autism's links to PTEN. They do reference the outrageous accusations made by the New York Times in their article as well. According to Forbes, PTEN is the gene that regulates cell cycles and mutations to this gene have effects that are not just cancerous. PTEN's primary function is to keep cells from dividing out of control, it is also known as the tumor suppressor gene. Of course a mutation in this area could cause tumors to grow, since the cells are not being regulated by PTEN, but that is no guarantee that they will. They also point out that mutations to PTEN cause a type of Autism that is part of a syndrome that impacts head circumference, macrocephaly, along with other characteristics unique to its own disorder. Forbes reports that scientists have known about the link between certain types of Autism and PTEN for almost five years. Approximately 1 in 10 individuals with PTEN mutations also have Autism, which makes a PTEN mutation a risk, not a cause of ASD. Researchers believe that a PTEN mutation, along with other genetic variants may cause Autism in some individuals. Forbes makes a very important statement and I am going to quote it verbatim because it is put so well: "The mutations in the PTEN gene that are linked to autism tend to be different from those for PTEN-associated cancer." In fact a PTEN link to Autism would only affect 1% of the Autism population.

In 2008 SFARI published an article: Autism and cancer share genetic roots, researchers find. During a study which included 18 genes which may impact Autism, researchers found PTEN, TSC1, and TSC2, play a prominent role in cancers and also are linked to some cases of Autism. In mouse studies, removing these genes caused enlarged neurons, seizures, and Autism-like behaviors. For some children with Autism, researchers who suspect PTEN, TSC1, or TSC2, may use a cancer treating drug, Rapamycin, to help treat behaviors associated with Autism. (As you know there is no cure for Autism.) Researchers say that only 2% of those with Autism will have it due to a mutation on one of the three genes listed, but it could help point to the region of genes where things are going wrong.

So what other disorders are associated with Autism and cancer?

There is a type of disorder that changes skin pigmentation and spurs the growth of tumors along the skin, brain and other body parts. It is Neurofibromatosis type 1 (NF1)and according to a 2014 SFARI article approximately 1/4th of those with NF1 also have Autism. NF1 is part of a family of disorders, which are extremely rare, and impact chromosome 16 along with RAS pathways. RAS impacts disorders like fragile X syndrome and TS. (To understand more about Fragile X, please see our blog series Understanding Genetics.) In the UK researchers studying a group of 207 children diagnosed with NF1 and administered an Autism screening questionnaire, the Social Responsiveness Scale, to half of them. Researchers invited a smaller group of these children to undergo further assessment and only 47 committed. So of their group of 47 children they conducted in person assessments. They found that 14 of the 47 had Autism, 13 showed some symptoms of Autism, and 20 did not have Autism. Based on this information they were able to estimate that as many as 45% of children with NF1 show features of Autism and 24.9% will receive a diagnosis of Autism. Based on some of this research, scientists believe in cases of NF, the cause of Autism may be due to a single gene, but more research is needed to prove this theory. 

So what about RAS diseases, without NF involvement? Again a 2013 SFARI article: Cancer pathway connects autism to set of rare disorders, answers our question. Citing an article published in the Journal of Medical Genetics this article states that one in four individuals diagnosed with RAS disorders also have Autism. The four RAS diseases are: Neurofibromatosis Type 1 (NF1), Noonan Syndrome, Costello Syndrome, and Cardio-facio-cutaneous Syndrome (CFC) (to learn more about any of these disorders please click on the name). RAS refers to the pathway of cells that signal the regulation of growth and development of all other cells. Mutations of RAS may lead to cancer, but may also influence the growth of cells like neurons. Of all the RAS disorders, NF1 has the strongest documented ties to Autism. 

Turner Syndrome vs Noonan Syndrome

As you can see the pathways of genes that have been linked to cancer, may play a role when mutated and lead to Autism. It is important for you as a parent to remember first, that these disorders are rare. They are usually discovered very quickly, and if your loved one has not yet been diagnosed with any of the disorders mentioned above, then it is very unlikely that they will not be. What this research does show us is a pathway that can be further studied in order to treat SOME types of Autism. It also gives great hope that the scientific leaps that are being made in this area will bleed over into other forms of Autism and better treatments could be established from it. 

Of course if you suspect any type of disease or disorder described in this post, I strongly advise you immediately speak to your pediatrician or family doctor. 

We hope this has helped you with an entry level understanding of the link between some genetics with ties to both cancer and Autism, but also explained the difference in their mutations. Please follow us on Facebook and Pinterest!