Genetics expert rejects autism inbreeding claims as misinformation

A senior Caribbean scientist is pushing back against social media claims that autism is caused by inbreeding, saying the argument has no scientific basis and can spread harmful misunderstanding.

Dr Wayne McLaughlin, director of the Caribbean Institute for Genomic Medicine, CARIGEN, and deputy dean of Basic Medical Sciences at The University of the West Indies, said autism spectrum disorder, ASD, cannot be explained in that simple way. He said conditions affecting brain development usually involve several biological and environmental influences, not a straightforward passing down of one so-called bad gene from parent to child.

"That is completely different," McLaughlin said, distinguishing inherited genetic illnesses from conditions connected to how the brain develops.

According to him, neurodevelopmental conditions can arise when the brain's development is altered or interrupted before birth. "Neurodevelopmental conditions wouldn't have anything to do with parents transferring a bad gene in that way. During development, something could change or go wrong, and that affects the outcome. It can involve both genetics and environmental factors -- there are a lot of things at play," he said.

ASD is a developmental condition linked to differences in the brain. People on the autism spectrum may experience challenges in areas such as social communication and interaction, with the effects varying according to where they fall on the spectrum.

McLaughlin's comments come as misinformation continues to move across social media, with some posts attempting to connect autism to family genetic patterns in a misleading way. He warned that such claims disregard long-standing scientific work and may worsen stigma toward people with autism as well as families affected by inherited disorders.

He said there are indeed medical conditions that can run through families, but those conditions operate through different biological mechanisms. Sickle cell disease, diabetes and some cancers can appear across generations through identifiable genetic patterns.

"What happens when closely related individuals have children is that there may be genes from each parent that carry some disease," McLaughlin said. "These genes are usually in a recessive form, meaning they don't show. Only when two of those genes come together, then that disease will be expressed."

Put another way, someone may have a harmful gene without showing signs of illness. If both parents carry the same recessive gene, however, their child may have a chance of developing the condition linked to it.

"When you do a cross between two individuals, it could happen that the two recessive genes come together and that means the disease will be expressed," McLaughlin said.

He added that the outcome depends heavily on which genes are involved. "Genetics can cause issues with the eyes, the vision could be very blurred to the extent they have to wear glasses. There could be certain expressions of blood diseases like hemophilia and there are many others," he said.

Medical experts also note that carriers of some genetic traits may look and feel healthy, while still being able to pass those traits to their children.

Polygenics Consulting, described as a leading DNA testing company, said shared ancestry in populations such as Jamaica can mean relatives or people from the same community may unknowingly carry the same recessive gene.

"This significantly increases the likelihood of inherited conditions appearing in children when both parents are carriers," Polygenics said.

The company said genetic screening before childbirth is not a routine step for most Jamaican families. It said that without preventative testing, people may be more likely to carry and pass on recessive genetic conditions without knowing.

"We strongly encourage individuals and couples to consider proactive testing," Polygenics said. "Investing in genetic awareness before starting a family can significantly reduce uncertainty and improve long-term health outcomes," it added.