A gene is an instruction to assemble proteins, which are structures essential for the formation and proper functioning of our body. The MSL2 gene gives instructions for the formation of the MSL2 protein, which is thought to play an important role in brain development and to regulate other important genes. Variants in the MSL2 gene can affect the MSL2 protein production, causing KBHS. They can be diagnosed by genetic testing, usually performed on a blood sample.