ALAD and hepatic porphyria: Additionally, ALA (delta-aminolevulinic acid) dehydratase deficiency porphyria (also known as ALAD deficiency or Doss porphyria) is an autosomal recessive disease caused by biallelic variants on ALAD gene, which is responsible for the production of delta-aminolevulinate dehydratase enzyme (1, 2).