Results of the largest autism study to use whole genome sequencing suggest that no two autism cases are the same, even if they come from the same family.

The study, published online Monday in the journal Nature Medicine, shows that there is a large genetic diversity in autism. It also underscores the need to do whole genome sequencing on patients, Dr. Stephen Scherer from Toronto's Hospital for Sick Children said in a statement.

"We already knew that there are many differences between autism cases, but our recent findings firmly nail that down," he said. "It shows that a full assessment of each individual's genome is needed to determine how to best use knowledge of their own genetic makeup for autism treatment."

For the study, researchers analyzed the DNA of 85 different families, each with two children with autism. Whole genome sequencing technology was used to detect any genetic mutations in the children.

Scherer said the results showed that no two autism cases are the same, even if they come from the same family.

"We believe each child with autism is like a snowflake; one is unique from another. Surprisingly, our research found that in more cases than not, even siblings can have two different 'forms' of autism," he said.

Scherer said the results will have a large impact on the field of genetics and DNA analysis.

"This means we cannot just look at parts of the DNA if we want to fully understand the underpinnings of autism and other disorders – we need to analyze the entire genome," he said.

The data collected for the study is part of a larger project named MSSNG, headed by Autism Speaks and Google. The goal of the project is to sequence the genomes of 10,000 families with autism, and make the data open-source and accessible to researchers from around the world.