The KCNMA1 gene is found on chromosome 10 and codes for a potassium (K+) ion channel that is present in our neuronal and muscular tissues. The KCNMA1 channel (also called the ‘BK’ channel for ‘Big K+’) is responsible for regulating potassium flow out of cells, which shapes electrical signals that neuronal firing and muscle movement. When a change in the DNA within the KCNMA1 gene occurs (‘KCNMA1 variant’), the function of the potassium channel can change. This change in channel activity is thought to change neuronal activity to cause the symptoms associated with KCNMA1 channelopathy.
There are several different types of variants that can occur in the KCNMA1 gene sequence. Some variants cause increased or new potassium channel activity; these are known as ‘Gain-Of-Function’ variants. Other variants cause decreased potassium channel activity; these are known as ‘Loss-Of-Function’ variants. Finally, there are some variants that need further investigation to determine their effect on potassium channel activity; these are known as variants of unknown significance.
We don’t fully understand how specific KCNMA1 variants dictate the symptoms that patients experience. More investigation is required to study this question for the benefit of patients and their families.
KCNMA1