Mom has had frequent leg cramps all her life?

Lately, her cramps have been coming on more frequently. They are HORRIBLY painful. She has tried stretching and all that, potium seems to make it worse. Everytime a cramp takes over her, I run to her with a heating pad, many fleece blankets, warm water, a brown bag for her to breathe into, and a pain relieving pill. It's become a routine. It's a VERY serious thing. A few times in her life, she had cramps while walking in the street. Once, she stopped right in the middle of a big city crosswalk just because of her cramp. Boy, she held up traffic. Is there any condition that describes this? My brother gets frequent cramps too, but not me... Is it genetic? My dad doesn't get cramps.