Scientists discover 'exciting' link between autism in children and gut bacteria that could help 'massive backlog' in diagnosis

The findings by researchers in Hong Kong, suggest that specific components of the gut microbiome — microorganisms, including bacteria, fungi, and viruses, that live in the digestive tracts of animals — could provide a new way of diagnosing the condition. 

Although the results, published in the Nature Microbiology journal, are novel, experts say they are excited because it could help address the 'massive backlog' in people waiting to be seen.

Autism, also called autism spectrum disorder (ASD), is a lifelong, developmental condition. It affects the way a person communicates, interacts and processes information.

Usually no lab tests are required for an autism diagnosis only observation by a specialist is needed. But in some cases children are waiting up to four years for an autism diagnosis.

Dr Elizabeth Lund, an independent consultant in nutrition and gastrointestinal health, who was not involved in the study, said: 'The idea that analysis of stool samples may aid in diagnosis is very exciting, as currently there is a massive backlog in children and adults waiting to be assessed.

'The current process is very lengthy and there is a shortage of clinicians such as psychologists and psychiatrists trained to carry out a proper diagnosis.'

She added: 'The researchers quite rightly point out that this data cannot say whether the different microbiome causes ASD or whether differences in the diet, or other environmental factors, associated with children with ASD lead to the observed differences.

'However, in my opinion, dietary preferences in people with ASD are so diverse they are unlikely to cause a consistent difference in the gut microbiome.'

According to the National Autistic Society, more than one in 100 people are on the autism spectrum and there are about 700,000 autistic adults and children in the UK.

Signs of autism adults include not understanding how others are feeling, getting anxious about social situations, having a strict routine or seeming blunt without meaning to.

Autistic children may avoid eye contact and not respond to their name being called, among other symptoms.

Siew Ng, from the Chinese University of Hong Kong, and colleagues analysed stool samples from 1,627 children aged one to 13, with or without ASD.

They found that specific bacterial and non-bacterial components of the gut microbiome and their functions could contribute to autism spectrum disorder (ASD) in both male and female children.

Taking into consideration additional factors including diet, medication and other health conditions, they identified that a number of different components of the microbiome were altered in children with ASD.

What is autism? By The National Autistic Society

The researchers created a model based on 31 different microbes and functions that made diagnosis more accurate, compared with just looking at one component, for example, bacteria.

Professor Bhismadev Chakrabarti, research director of the Centre for Autism at the University of Reading, who did not take part in the research, said: 'What is exciting about this study is that it opens up the possibility of investigating specific biochemical pathways and their impact on different autistic features.

'It could also provide new ways of detecting autism, if microbial markers turn out to strengthen the ability of genetic and behavioural tests to detect autism.

'A future platform that can combine genetic, microbial, and simple behavioural assessments could help address the detection gap.

'With the results of this study, the lens through which we view microbiota within autism has definitely broadened.'

WHAT IS AUTISM? 

Autism is a life-long developmental disability, which affects how people act on a wide-ranging spectrum.

According to the Centers for Disease Control and Prevention, autistic people can have trouble with social, emotional and communication skills.

Others can find bright lights or loud noises overwhelming and stressful, or display repetitive behaviours.

Autism is not an illness or disease. 

How common is it?

It is estimated that around 700,000 people, including adults and children, in the UK have an autism diagnosis.

According to a Newcastle University study published in 2021, around one in 57 (1.76 per cent) children in the UK is on the spectrum.

In the US, the Centers for Disease Control and Prevention estimate 5.4million adults, some 2.2 per cent of the population, are autistic.

People from all nationalities and cultural, religious and social backgrounds can have autism.

Rates are up to five times higher in men and boys, though.

The exact reason remains unclear, but some studies suggest boys are at greater risk of the varied genetic causes of autism.

Researchers also believe many girls may be 'flying under the radar', as they struggle to get a diagnosis, receive a diagnosis late in life or are misdiagnosed with conditions other than autism.

Are there different types? 

Previously, autism was broken down into different diagnoses, including Asperger's syndrome, autistic disorder, Kanner's syndrome, childhood autism, atypical autism and pervasive development disorder not otherwise specified (PDD-NOS).

As each diagnosis shared characteristics of autism, they were replaced with autism spectrum disorder, which is now the umbrella term for the group.

However, some people with a diagnosis of Asperger's still choose to use the term.

According to the National Autistic Society, people with Asperger's do not have the learning disabilities that many autistic people have. The NHS says that some people call this 'high-functioning autism'.

What causes it?

Despite years of research, scientists do not know what causes autism.

Instead, studies have suggested it may develop from a combination of genetic and environmental influences.

Concerns about a possible link between MMR vaccines and autism were raised in the late 1990s.

But numerous scientific studies have since shown that there is no link at all between vaccines — or any of their ingredients — and autism.

Bad parenting is also not a cause.