What would happen to an infant whose nerve fibers did not myelinate properly?

The brain receives huge amounts of information from outside our body via our five senses (vision, sound, taste, touch, and smell), integrates this information, and orders our muscles to take action. The membrane that makes all this happen so efficiently is called Myelin... *Without this all these things would be much slower and less efficient.*

My funny joke is my friend can no roll over