Can Genetic Testing Help Shed Light on the Autism Epidemic?
A little boy standing by a window in contemplation. (© altanaka/Fotolia)
Autism cases are still on the rise, and scientists don't know why. In April, the Centers for Disease Control (CDC) reported that rates of autism had increased once again, now at an estimated 1 in 59 children up from 1 in 68 just two years ago. Rates have been climbing steadily since 2007 when the CDC initially estimated that 1 in 150 children were on the autism spectrum.
Some clinicians are concerned that the creeping expansion of autism is causing the diagnosis to lose its meaning.
The standard explanation for this increase has been the expansion of the definition of autism to include milder forms like Asperger's, as well as a heightened awareness of the condition that has improved screening efforts. For example, the most recent jump is attributed to children in minority communities being diagnosed who might have previously gone under the radar. In addition, more federally funded resources are available to children with autism than other types of developmental disorders, which may prompt families or physicians to push harder for a diagnosis.
Some clinicians are concerned that the creeping expansion of autism is causing the diagnosis to lose its meaning. William Graf, a pediatric neurologist at Connecticut Children's Medical Center, says that when a nurse tells him that a new patient has a history of autism, the term is no longer a useful description. "Even though I know this topic extremely well, I cannot picture the child anymore," he says. "Use the words mild, moderate, or severe. Just give me a couple more clues, because when you say autism today, I have no idea what people are talking about anymore."
Genetic testing has emerged as one potential way to remedy the overly broad label by narrowing down a heterogeneous diagnosis to a specific genetic disorder. According to Suma Shankar, a medical geneticist at the University of California, Davis, up to 60 percent of autism cases could be attributed to underlying genetic causes. Common examples include Fragile X Syndrome or Rett Syndrome—neurodevelopmental disorders that are caused by mutations in individual genes and are behaviorally classified as autism.
With more than 500 different mutations associated with autism, very few additional diagnoses provide meaningful information.
Having a genetic diagnosis in addition to an autism diagnosis can help families in several ways, says Shankar. Knowing the genetic origin can alert families to other potential health problems that are linked to the mutation, such as heart defects or problems with the immune system. It may also help clinicians provide more targeted behavioral therapies and could one day lead to the development of drug treatments for underlying neurochemical abnormalities. "It will pave the way to begin to tease out treatments," Shankar says.
When a doctor diagnoses a child as having a specific genetic condition, the label of autism is still kept because it is more well-known and gives the child access to more state-funded resources. Children can thus be diagnosed with multiple conditions: autism spectrum disorder and their specific gene mutation. However, with more than 500 different mutations associated with autism, very few additional diagnoses provide meaningful information. What's more, the presence or absence of a mutation doesn't necessarily indicate whether the child is on the mild or severe end of the autism spectrum.
Because of this, Graf doubts that genetic classifications are really that useful. He tells the story of a boy with epilepsy and severe intellectual disabilities who was diagnosed with autism as a young child. Years later, Graf ordered genetic testing for the boy and discovered that he had a mutation in the gene SYNGAP1. However, this knowledge didn't change the boy's autism status. "That diagnosis [SYNGAP1] turns out to be very specific for him, but it will never be a household name. Biologically it's good to know, and now it's all over his chart. But on a societal level he still needs this catch-all label [of autism]," Graf says.
"It gives some information, but to what degree does that change treatment or prognosis?"
Jennifer Singh, a sociologist at Georgia Tech who wrote the book Multiple Autisms: Spectrums of Advocacy and Genomic Science, agrees. "I don't know that the knowledge gained from just having a gene that's linked to autism," is that beneficial, she says. "It gives some information, but to what degree does that change treatment or prognosis? Because at the end of the day you have to address the issues that are at hand, whatever they might be."
As more children are diagnosed with autism, knowledge of the underlying genetic mutation causing the condition could help families better understand the diagnosis and anticipate their child's developmental trajectory. However, for the vast majority, an additional label provides little clarity or consolation.
Instead of spending money on genetic screens, Singh thinks the resources would be better used on additional services for people who don't have access to behavioral, speech, or occupational therapy. "Things that are really going to matter for this child in their future," she says.
Phil Gutis, an Alzheimer's patient who participated in a failed clinical trial, poses with his dog Abe.
Phil Gutis never had a stellar memory, but when he reached his early 50s, it became a problem he could no longer ignore. He had trouble calculating how much to tip after a meal, finding things he had just put on his desk, and understanding simple driving directions.
From 1998-2017, industry sources reported 146 failed attempts at developing Alzheimer's drugs.
So three years ago, at age 54, he answered an ad for a drug trial seeking people experiencing memory issues. He scored so low in the memory testing he was told something was wrong. M.R.I.s and PET scans confirmed that he had early-onset Alzheimer's disease.
Gutis, who is a former New York Times reporter and American Civil Liberties Union spokesman, felt fortunate to get into an advanced clinical trial of a new treatment for Alzheimer's disease. The drug, called aducanumab, had shown promising results in earlier studies.
Four years of data had found that the drug effectively reduced the burden of protein fragments called beta-amyloids, which destroy connections between nerve cells. Amyloid plaques are found in the brains of patients with Alzheimer's disease and are associated with impairments in thinking and memory.
Gutis eagerly participated in the clinical trial and received 35 monthly infusions. "For the first 20 infusions, I did not know whether I was receiving the drug or the placebo," he says. "During the last 15 months, I received aducanumab. But it really didn't matter if I was receiving the drug or the placebo because on March 21, the trial was stopped because [the drug company] Biogen found that the treatments were ineffective."
The news was devastating to the trial participants, but also to the Alzheimer's research community. Earlier this year, another pharmaceutical company, Roche, announced it was discontinuing two of its Alzheimer's clinical trials. From 1998-2017, industry sources reported 146 failed attempts at developing Alzheimer's drugs. There are five prescription drugs approved to treat its symptoms, but a cure remains elusive. The latest failures have left researchers scratching their heads about how to approach attacking the disease.
The failure of aducanumab was also another setback for the estimated 5.8 million people who have Alzheimer's in the United States. Of these, around 5.6 million are older than 65 and 200,000 suffer from the younger-onset form, including Gutis.
Gutis is understandably distraught about the cancellation of the trial. "I really had hopes it would work. So did all the patients."
While drug companies have failed so far, another group is stepping up to expedite the development of a cure: venture philanthropists.
For now, he is exercising every day to keep his blood flowing, which is supposed to delay the progression of the disease, and trying to eat a low-fat diet. "But I know that none of it will make a difference. Alzheimer's is a progressive disease. There are no treatments to delay it, let alone cure it."
But while drug companies have failed so far, another group is stepping up to expedite the development of a cure: venture philanthropists. These are successful titans of industry and dedicated foundations who are donating large sums of money to fill a much-needed void – funding research to look for new biomarkers.
Biomarkers are neurochemical indicators that can be used to detect the presence of a disease and objectively measure its progression. There are currently no validated biomarkers for Alzheimer's, but researchers are actively studying promising candidates. The hope is that they will find a reliable way to identify the disease even before the symptoms of mental decline show up, so that treatments can be directed at a very early stage.
Howard Fillit, Founding Executive Director and Chief Science Officer of the Alzheimer's Drug Discovery Foundation, says, "We need novel biomarkers to diagnose Alzheimer's disease and related dementias. But pharmaceutical companies don't put money into biomarkers research."
One of the venture philanthropists who has recently stepped up to the task is Bill Gates. In January 2018, he announced his father had Alzheimer's disease in an interview on the Today Show with Maria Shriver, whose father Sargent Shriver, died of Alzheimer's disease in 2011. Gates told Ms. Shriver that he had invested $100 million into Alzheimer's research, with $50 million of his donation going to Dementia Discovery Fund, which looks for new cures and treatments.
That August, Gates joined other investors in a new fund called Diagnostics Accelerator. The project aims to supports researchers looking to speed up new ideas for earlier and better diagnosis of the disease.
Gates and other donors committed more than $35 million to help launch it, and this April, Jeff and Mackenzie Bezos joined the coalition, bringing the current program funding to nearly $50 million.
"It makes sense that a challenge this significant would draw the attention of some of the world's leading thinkers."
None of these funders stand to make a profit on their donation, unlike traditional research investments by drug companies. The standard alternatives to such funding have upsides -- and downsides.
As Bill Gates wrote on his blog, "Investments from governments or charitable organizations are fantastic at generating new ideas and cutting-edge research -- but they're not always great at creating usable products, since no one stands to make a profit at the end of the day.
"Venture capital, on the other end of the spectrum, is more likely to develop a test that will reach patients, but its financial model favors projects that will earn big returns for investors. Venture philanthropy splits the difference. It incentivizes a bold, risk-taking approach to research with an end goal of a real product for real patients. If any of the projects backed by Diagnostics Accelerator succeed, our share of the financial windfall goes right back into the fund."
Gutis said he is thankful for any attention given to finding a cure for Alzheimer's.
"Most doctors and scientists will tell you that we're still in the dark ages when it comes to fully understanding how the brain works, let alone figuring out the cause or treatment for Alzheimer's.
"It makes sense that a challenge this significant would draw the attention of some of the world's leading thinkers. I only hope they can be more successful with their entrepreneurial approach to finding a cure than the drug companies have been with their more traditional paths."
Many patients in the African-American community are skeptical of new experimental treatments, thanks to a history of medical exploitation in the 20th century.
If any malady proves the fragile grace of the human genome, it is sickle cell disease.
If experimental treatments receive regulatory approval, it would be a watershed breakthrough for tens of thousands of Americans.
It occurs because of a single "misspelled" letter of DNA, causing red blood cells to run low on oxygen and transforming the hemoglobin in each cell into a stiff rod. Normally round cells become rigid crescents that hamper the flow of blood throughout the body, like leaves clumping in a drain.
Strokes in toddlers are merely the beginning of the circulatory calamities this disease may inflict. Most sickled cells cannot carry oxygen through the body, causing anemia as well as excruciating chronic pain. Older patients are at risk of kidney failure, heart disease and all the other collateral damage caused by poor circulation. Few live beyond middle age.
The only way to cure it has been through a bone marrow transplant from a donor, which requires not only a closely matching volunteer, but bouts of chemotherapy to allow new stem cells to take root, as well as rounds of immunosuppressive drugs that may last for years.
Recent advances in genomic medicine may soon alter the disease's outlook, although many obstacles remain.
In one treatment under development, patient's skin cells are converted into stem cells, allowing them to be inserted into the bone marrow without the need for a donor. Another treatment known as gene therapy involves replacing the aberrant gene in the patient's body with new genetic material.
Although both remain in clinical trials -- and also require at least chemotherapy -- they have shown promise. Matthew Hsieh, a hematologist and staff scientist with the National Heart Lung and Blood Institute in Maryland, has performed about 10 gene therapy procedures over the past three years as part of a clinical trial. Ongoing tweaks in the procedure have led to the blood in more recent patients showing sickle cell trait -- not a perfect outcome, but one that leaves patients with far fewer symptoms than if they have the full-blown disease.
If one or both treatments receive regulatory approval, it would be a watershed breakthrough for the tens of thousands of Americans who suffer from the disease.
Yet it is entirely possible many patients may decline the cure.
A Painful History
The vast majority of sickle cell sufferers in the U.S. -- well beyond 90 percent -- are African-American, a population with a historically uneasy relationship toward healthcare.
"There is a lot of data on distrust between African-Americans and American medical institutions," says J. Corey Williams, a psychiatrist with the Children's Hospital of Philadelphia who has written extensively on racial disparities in healthcare. "It comes from a long legacy of feeling victimized by medicine."
"What you hear from many patients is 'I am not going to be your guinea pig, and I am not going to be experimented on.'"
As a result, Williams is among several clinicians interviewed for this story who believe a cure for sickle cell disease would be embraced reluctantly.
"What you hear from many patients is 'I am not going to be your guinea pig, and I am not going to be experimented on.' And so the history of African-Americans and research will manifest as we develop gene therapies for [these] patients," says Christopher L. Edwards, a clinical psychologist and researcher with the Maya Angelou Center for Health Equity at the Wake Forest University School of Medicine.
Fear among African-Americans of becoming guinea pigs is well-founded. The first c-sections and fistula repairs occurring in North America were performed on enslaved women -- all without consent and virtually none with anesthesia.
Modern 20th century medicine led to the Tuskegee syphilis experiments conducted by the U.S. Public Health Service. Researchers withheld treatment from some 400 African-American men from the 1930s well into the 1970s to observe how they reacted to the disease -- even though curative antibiotics had been around for decades. Only news reports ended the experiment.
The long-standing distrust of American healthcare in the African-American community is also baked into the care provided to sickle cell patients. Despite affecting one in 365 African-Americans, there is no disease registry to assist clinical trials, according to Mary Hulihan, a blood disorders epidemiologist with the Centers for Disease Control and Prevention. Edwards says many sufferers are suspicious of being monitored.
Meanwhile, only two drugs are available to alleviate the worst symptoms. The first one, hydroxyurea, received FDA approval only in 1998 -- nearly 90 years after the disease was first diagnosed. Moreover, Edwards says that some sufferers shy away from using hydroxyurea because it is also used to treat cancer. It's part of what he calls the "myth and folklore" in the African-American community about sickle cell disease.
Economics plays a role as well in the often-fragmented care such patients receive. According to CDC data, many patients rely extensively on public insurance programs such as Medicaid, whose coverage varies from state to state.
A Tough Transition
Edwards notes that sickle cell sufferers usually receive good care when they're children because of support provided by family members. But that often breaks down in adulthood. According to CDC data, an adult sickle cell patient visits a hospital emergency room three times as often as a child patient.
The consensus is that the path to a medical cure for sickle cell will first need to be smoothed over with a talk cure.
Modupe Idowu, a hematologist with the University of Texas Health system, estimates that there are perhaps a dozen comprehensive care centers for the estimated 100,000 sickle cell patients in the U.S., including the one she operates in Houston. That means a significant proportion of those afflicted are on their own to procure care.
And since many patients are on Medicaid, "a lot of hematologists that train to take care of blood disorders, many are not interested in treating [sickle cell disease] because the reimbursement for providers is not great," Idowu says.
Hsieh acknowledges that many of his patients can be suspicious about the care they are receiving. Frustration with fragmented care is usually the biggest driver, he adds.
Meanwhile, the skepticism that patients have about the treatments they seek is often reciprocated by their caregivers.
"The patients have experiences with medication and know what works at a very young age (for their pain)," Edwards says. Such expertise demonstrated by an African-American patient often leads to them being labeled as narcotics seekers.
The Correct Path
This all begs the question of how to deploy a cure. Idowu, who regularly holds town hall-style meetings with Houston-area patients, often must allay anxieties. For example, the gene therapy approach uses a harmless virus to transport new genetic material into cells. That virus happens to be a benign version of HIV, and convincing patients they won't be infected with HIV is a fraught issue.
The consensus is that the path to a medical cure for sickle cell will first need to be smoothed over with a talk cure.
Idowu tries to hammer home the fact that patients are afforded vastly more protections than in the past. "There are a lot of committees and investigational review boards that keep track of clinical trials; things just don't happen anymore as they did in the past," she says. She also believes it helps if more providers of color communicate to patients.
Hsieh is very straightforward with his patients. He informs them about the HIV vector but assures them no one has ever tested positive for the virus as a result of its use.
Edwards notes that since many patients suffer psychosocial trauma as a result of their chronic pain, there already is some counseling infrastructure in place to help them cope. He believes such resources will have to be stretched further as a cure looms closer.
In the absence of formal mental health services, straight talk may be the best way to overcome wariness.
"If patients have misgivings, we try our best to address them, and let them know at the end of the day it is their decision to make," Hsieh says. "And even the patients who have gone through the gene therapy and it didn't work well -- they're still glad they took the chance."