If a baby's skull hardens or closes along any of the sutures or the soft spot, than it can affect the growth of the child's brain because nearly 80 percent of the human brain's growth occurs from birth to 3 years old, according to the UNC School of Medicine. In addition to limiting the size of the brain, it can cause the brain to not form correctly and can be the indicator or cause of a number of syndromes or learning issues.
There are multiple reasons that these types of issues can occur with an infant's skull, with the most common being pressure put on the skull in the womb. If a fetus gets wedged oddly, the pressure on the skull can signal the body that the growth is finished. This can start the fusing process.