Researchers at the Whitehead Institute have found a link between deletions in particular genes and certain brain and body traits such as seizures, hyperactivity, enlarged head size, and obesity.
The two genes—fam57ba and doc2a—reside in the 16p11.2 region of human chromosome 16. Approximately 1 in 2000 people worldwide have deletions in this region. These deletions are associated with autism spectrum disorder, developmental delays, intellectual disabilities, seizures, obesity and other brain and body symptoms.
To find how this region is associated with these symptoms, the team used a zebrafish model to map genotypic changes to phenotypic ones. The researchers identified two genetic factors: fam57ba, which encodes a ceramide synthase that makes a type of lipid, and doc2a, which encodes a regulator of secretin. When the scientists deleted one copy of one of the genes in zebrafish, there was little noticeable change. However, deleting one copy of both genes simultaneously revealed significant phenotypic changes. These zebrafish exhibited hyperactivity, increased chance of seizures, higher body and head size and higher fat content. The findings were published in Human Molecular Genetics.
So far, the mechanisms underlying the brain/body connection have not been well understood. This study offers a little more insight into this system and indicates that one of the identified genes, fam57ba, may play a role in the connection between metabolism and brain function.
"Our data suggest that there may be metabolic genes involved in human neurodevelopmental disorders," said Whitehead Institute Member, Hazel Sive. "This is a nascent field, that we're very interested in going forward."