The main suspect for a patient to have XP is clinical symptoms. Primary care physicians, paediatricians or urgencies doctors are the first barrier entry to health care for these children. Often, it is a rare condition not very well known what can promote a delay in the diagnosis process. When a child is showing hyperpigmentation or/and sunburns after a short period sun exposure, genetic analysis is done to identify if any of the involved genes described before (section Types of XP) is mutated. When testing positive for this genetic analysis, the diagnosis is definitive and measures should be taken rapidly.