About one person in ten is born with a lumbosacral transitional vertebra, and in some of them it becomes a source of persistent low back, buttock or hip pain that is invisible, fluctuating and often unnamed for years. This guide is for the partner, parent, child, sibling, housemate or friend of someone with Bertolotti syndrome. It explains what the condition is in plain terms, why the diagnosis usually took so long, what the pain does to daily life, what diagnosis and treatment involve, and what family and friends can do that helps: believing the pain, offering specific help, keeping the invitation open, planning for recovery days, sharing the load out loud, and coming to appointments with the folder. It covers children, the weeks around surgery, money and travel in the Australian system, and looking after yourself as a carer. Every clinical statement is referenced to the published evidence.