Test based on 31 genetic markers could be used to calculate any individual’s yearly risk for onset of disease 
 
 Scientists have developed a new genetic test for Alzheimer’s risk that can be used to predict the age at which a person will develop the disease. 
 
 A high score on the test, which is based on 31 genetic markers, can translate to being diagnosed many years earlier than those with a low-risk genetic profile, the study found. Those ranked in the top 10% in terms of risk were more than three times as likely to develop Alzheimer’s during the course of the study, and did so more than a decade before those who ranked in the lowest 10%. 
 
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 Rahul Desikan, of the University of California – who led the international effort, said the test could be used to calculate any individual’s risk of developing Alzheimer’s that year. 
 
 “That is, if you don’t already have dementia, what is your yearly risk for AD onset, based on your age and genetic information,�? he said. 
 
 
 
 The so-called polygenic hazard score test was developed using genetic data from more than 70,000 individuals, including patients with Alzheimer’s disease and healthy elderly people. 
 
 
 
 It is already known that genetics plays a powerful role in Alzheimer’s. Around a quarter of patients have a strong family history of the disease, and scientists have shown this is partly explained by a gene called ApoE, which comes in three versions, and is known to have a powerful influence on the risk of getting the most common late-onset type of Alzheimer’s. One version of ApoE appears to reduce risk by up to 40%, while those with two copies (one from each parent) of the high-risk version can increase risk by 12 times. 
 
 The latest study takes a new approach, showing that, aside from ApoE, there are thousands of background genetic variations that each have a tiny influence on Alzheimer’s risk, but whose cumulative influence is substantial. 
 
 The researchers first identified nearly 2,000 single letter differences in the genetic code (known as SNPs) and, after ranking them for influence, developed a test based on 31 of the markers. The test was then used to accurately predict an individual’s risk of getting the disease in an independent patient cohort. 
 
 In people with the high-risk version of ApoE, those ranked in the top 10% of risk on the new test got Alzheimer’s at an average age of 84 years, compared with 95 years for those ranked in the lowest 10%. 
 
 James Pickett, head of research at Alzheimer’s Society, said: “Preventing the development of dementia symptoms is the holy grail of Alzheimer’s research but to succeed we first need accurate methods to predict who is most likely to develop the condition. This study’s approach was fairly successful at predicting the likelihood of someone developing dementia over the coming year, but needs to be tested further in mixed, non-US populations.�? 
 
 Pickett added that, while the score could help to identify people for trials, it was too early to apply it as a genetic testing tool for use in the clinic. 
 
 Rosa Sancho, head of research at Alzheimer’s Research UK, said that while genetic makeup can influence the chances of developing dementia, a healthy diet, regular physical activity and remaining mentally active can also drive down the risk. “Genetics is only part of the story and we know that lifestyle factors also influence our risk of developing Alzheimer’s,�? she said. “The best current evidence points to habits we can all adopt to help lower our risk and indicates that what’s good for your heart is also good for the brain.�? 
 
 The findings are published in the journal PLOS Medicine. ||||| The mother and father watched as their 16-year-old daughter ate her pork chop and green beans across the kitchen table of their Mount Prospect home, grateful each time she swallowed without struggle. 
 
 She paused in between bites to sing a few lyrics of her favorite song. "We're all in this toge-e-ether," Hayley Koujaian crooned the theme from "High School Musical," a movie she loved as a little girl, before anyone could tell she was sick. 
 
 Hayley has a rare genetic disorder called Niemann-Pick Disease Type C, often dubbed childhood Alzheimer's because its symptoms are similar to those of adult dementia, though it's not the same disease. Memory, speech and mobility fade. It gets harder to eat and drink unaided. There is no treatment approved by the Food and Drug Administration, and young children with the disorder typically don't live past their teens. 
 
 "We all knew what the outcome was going to be if the disease progressed," said her father, Harry Koujaian. "There is only one outcome. That's why we were so desperate." 
 
 Yet the family has found hope in a promising experimental drug — and the local physician who helped them gain access. 
 
 Every two weeks, Dr. Elizabeth Berry-Kravis injects a treatment called cyclodextrin into Hayley via a spinal tap at Rush University Medical Center as her father holds her steady and her mother silently prays. Hayley is one of roughly 40 patients across the country using the investigational drug, hoping for future FDA approval. 
 
 Berry-Kravis, a pediatric neurologist, said there's initial evidence the injections could be staving off the disease's progression. Some skills even appear to be improving. 
 
 Before starting treatment a little more than two years ago, Hayley was functioning at the level of an 18-month-old, based on language and cognitive testing. Now her abilities closer match a 2 1/2 - or 3-year-old, Berry-Kravis said. Swallowing is much easier. Her gait is smoother, and she's less apt to fall. 
 
 Prior to treatment, speech therapists found Hayley had difficulty putting together a few words. Now she reads simple sentences, responds to short questions and even sings some of the songs from early childhood, before her mind began slipping away. 
 
 While the drug is still in clinical trials, it has significantly extended the lives of mice and cats with the disorder compared with those left untreated. 
 
 The Koujaians wonder whether it could be extending Hayley's life, too. 
 
 "We would not be here, like this," said her mother, Gail Koujaian, gesturing to her family sitting around the dinner table. "Maybe we would be pushing her wheelchair. Maybe we would be cleaning her feeding tube." Not like this, she said. 
 
 Niemann-Pick Type C treatment Nancy Stone / Chicago Tribune Harry Koujaian and his daughter, Hayley, wait for Dr. Elizabeth Berry-Kravis. Harry and Gail Koujaian brought their daughter, who has Niemann-Pick Disease Type C, to Chicago's Rush University Medical Center on Feb. 3, 2016, for one of a series of treatments with an experimental drug. Harry Koujaian and his daughter, Hayley, wait for Dr. Elizabeth Berry-Kravis. Harry and Gail Koujaian brought their daughter, who has Niemann-Pick Disease Type C, to Chicago's Rush University Medical Center on Feb. 3, 2016, for one of a series of treatments with an experimental drug. (Nancy Stone / Chicago Tribune) 
 
 Mysterious symptoms 
 
 Hayley was born Aug. 10, 1999, a chubby-cheeked baby with heart-shaped lips and no hint of any abnormality. 
 
 Gail and Harry Koujaian recall their daughter was just like any other toddler, running around with ease and learning how to read and write alongside the rest of her kindergarten friends. 
 
 Then in first grade, she mysteriously began falling behind. First teachers noticed she wasn't retaining information. There was odd clumsiness, bumping into walls and desks without explanation. Most alarming, she appeared to be losing abilities she once mastered. 
 
 Her mother noticed during Brownie troop meetings that all the other girls could walk alone across a long, thick tube on the playground. Gail Koujaian always had to hold her daughter's hand. 
 
 Then Hayley began erupting in seizures, sometimes several in one day. Medication after medication failed, and, at 11 she had brain surgery and her tissue was sent to a pathologist for testing. 
 
 Six months and a litany of tests later, the Koujaians got the devastating diagnosis: Niemann-Pick Type C, a fatal disease often appearing in children where naturally produced cholesterol accumulates and becomes toxic. There are about 500 cases diagnosed internationally. 
 
 Gail Koujaian recalls days when she would drop off her daughter at school and then cry in her car alone. The Koujaians started meeting other families with the genetic disorder from across the country, which was both comforting and terrifying. 
 
 "You've got kids who are dying, kids in wheelchairs, kids who can't eat, kids on feeding tubes," Harry Koujaian said. "It's a cruel disease." 
 
 It was another mom who told them about cyclodextrin, which appeared to help her own twin daughters. The National Institutes of Health had just begun an exploratory trial of the drug. The Koujaians jumped at the chance for Hayley to join the study, but she was found ineligible because of her uncontrolled seizures. 
 
 The only other option was to find a physician to file a compassionate-use request with the FDA, a complicated and lengthy process. The Koujaians weren't sure anyone would be able or willing to take on the burden. But they had just started seeing a new pediatric neurologist, Berry-Kravis, who found the most recent research for cyclodextrin so compelling, she wanted to give it a try. 
 
 "I can do this," the Koujaians remembered her saying. 
 
 Questions linger 
 
 Every other week, the Koujaians drive a few miles to pick up Berry-Kravis at her Des Plaines home, and they all travel together to the clinic at Rush. 
 
 Berry-Kravis usually discusses Hayley's progress, typing up her reports on a laptop in the front passenger seat as they sit in traffic on the Kennedy Expressway. It's like a house call in the family's 2006 green Honda Pilot. 
 
 Last week at Hayley's 56th treatment, she was put to sleep with melatonin, her thick brown ponytail spilling over the edge of the hospital table, as Berry-Kravis numbed her back with lidocaine. 
 
 The neurologist inserted a 3-inch needle with a pencil-point tip into Hayley's spinal canal, first removing 10 milliliters of fluid to be used for research. Hayley didn't open her eyes or appear to be in any pain. 
 
 The process has become routine for them. They intermittently joke and laugh softly so as not to wake her. 
 
 During these procedures, Gail Koujaian asks God to make sure Hayley doesn't have a seizure; Harry Koujaian wraps his arms around Hayley as a precaution, just in case she does. 
 
 Berry-Kravis started injecting the drug through the spinal tap when a car alarm went off on Harrison Street seven floors below. Hayley fidgeted a little, and her parents quickly steadied her as Berry-Kravis finished. Then they reclined the table, positioning Hayley's feet up, hoping the drug will drip from her spine to her brain as she continued to sleep.
– You have one of six possible variations of the APOE gene, having inherited one variant—e2, e3, or e4—from each parent. Reporting in the journal Neuron, University of Hawaii researchers found that the brain development of children as young as preschool age with two copies of e4 or one of e4 and one of e2 seem most adversely affected—an intriguing find in light of previous research that has linked the e4 variant to Alzheimer's. Researchers scanned the brains of 1,187 healthy people between the ages of 3 and 20 and found, for instance, that the size of the hippocampus tends to be smaller in those with the e2/e4 combination. They also found some kids with e4 didn't perform as well on tests of memory, though they caught up with their peers by age 10, reports HealthDay News. And while brain researcher Rebecca Knickmeyer, who didn't participate in the study but wrote an accompanying editorial, says the variants aren't necessarily predictive and people shouldn't start testing their kids, the research suggests that Alzheimer's may in fact be a developmental disorder, not strictly an aging one, reports the Los Angeles Times. That raises the possibility that adjustments to "diet or cognitive training" early on could change someone's "trajectory," per Knickmeyer. Three in four people have at least one copy of e3, which seems to offer a protective effect. About 14% of people have an e4 variant, which has been linked with an elevated risk of Alzheimer's, but Knickmeyer points out that there are many Alzheimer's patients without e4, and many with e4 who never develop Alzheimer's. (Some research suggests that memories lost to Alzheimer's are actually retrievable.)