A BRAF mutation in melanoma is a spontaneous change in the BRAF gene that causes it to function incorrectly. This can lead to uncontrolled cell growth, which can cause melanoma to grow faster. BRAF mutations can be caused by environmental factors or errors during cell division. Around 50% of melanomas have an acquired BRAF mutation, which means it develops after birth. Acquired changes are usually not passed down to children because they don't occur in sperm or egg cells. People can also inherit a BRAF mutation from their biological parents, but this is very rare and can cause serious health issues.