Partial tetrasomy of chromosome 3q and mosaicism in a child with autism.

Doctors looked at one young learners boy who had both autism and intellectual disability.

They checked his chromosomes and found an extra copy of part of chromosome 3q in some cells.

This mix of normal and abnormal cells is called mosaicism.

The boy carried a rare glitch: four copies of 3q instead of the usual two in about half his cells.

No one had ever linked this exact chromosome change to autism before.

Chicoine et al. (2015) pooled 57 male Rett cases and showed most have clear MECP2 mutations.

Guiomar’s boy lacked Rett features, so the new 3q finding adds a separate genetic road to autism.

Casey et al. (2009) explain that tiny genetic errors can disrupt brain growth through the mTOR pathway.

The 3q region holds genes that touch the same pathway, giving a possible reason why this boy had both autism and low IQ.

When a child presents with both autism and intellectual disability, consider ordering a full chromosome test.

Finding a rare copy-number change like 3q tetrasomy gives families a clearer cause and helps you plan realistic goals.

Share the report with the medical team so they can watch for any organ issues tied to 3q duplications.