Overview
A hepatic porphyria (or variegate porphyria) caused by monoallelic and biallelic variants in PPOX, presenting as a spectrum of disease (a semidominant inheritance pattern). Cases caused by monoallelic variants may have onset during adolescence or adulthood and are episodic characterized by abdominal pain, constipation, vomiting, muscular paralysis, and psychosis. Other symptoms may include abnormal blistering of the skin, cutaneous photosensitivity, and neuropathy.
Triggers precipitating acute attacks include estrogen/progesterone, oral contraceptives, alcohol, drugs, stress, or infections. Cases caused by biallelic variants, which reduce enzyme activity to <25% of normal, typically result in child or adolescent onset with greater severity. Symptoms for this extend to brachydactyly, clinodactyly, intellectual disability, nystagmus, myopia, growth retardation, and hyperpigmentation.