• Individuals with a documented diagnosis of a porphyria.

• For each type of porphyria, the inclusion criteria are based on

‣ Biochemical findings, as documented by laboratory reports (or copies) of porphyria-specific testing performed after 1980 (Absolute values are preferred for diagnostic biochemical thresholds. Fold increases in comparison to an upper (or lower) limit of normal (ULN or LLN) are also acceptable, but are complicated by considerable variation between laboratories in normal limits. Equivocal biochemical measurements may require confirmation by a consortium reference laboratory;)

⁃ molecular findings documenting the identification of a mutation in a porphyria-related gene.

• In addition, an individual or a parent or guardian must be willing to give written informed consent or assent, as appropriate.

• Provision is made for enrolling relatives who may not have symptoms but have biochemical or molecular documentation of a porphyria, or in the case of recessive disorders carry a disease-related mutation.