A Chinese woman has been found to be missing her cerebellum, a key part of the brain. The 24-year-old lives a normal life, but has some problems with walking steadily.

“Cerebellum” is Latin for “little brain”, and it’s an apt term. Although only making up around one-tenth of the brain in size, it contains around half the total neurons. It’s main role is in movement: not in initiating movement, but rather in receiving and processing sensory information and using this to fine tune movement and regulate balance.

A report in the journal Brain, covered by New Scientist, notes that the woman is only the ninth patient on record to be missing the entire cerebellum. It appears to be the first time the condition has been diagnosed and assessed in a living adult.

How and why she grew up without the cerebellum isn’t yet known. The space where it should be is filled with cerebospinal fluid.

Although the woman didn’t speak clearly until she was six, or walk until she was seven, doctors are reported as saying the effects now are mild. Although she has “mild to moderate motor deficiency” and “slightly slurred pronunciation” the effects are not as great as would be expected. She has no problems understanding words or expressing herself and she can walk without support.

It appears this is an example of the plasticity of the brain: its ability to adjust to damage or imperfections by having different parts of the brain switch to something other than their normal roles.

Wired makes the important points that we still don’t know the full extent of the effects the missing cerebellum has on the woman, and that it doesn’t necessarily contradict that idea that any form of serious brain trauma will have some long-term effects.