Citrullinemia is a rare metabolic disease and can rangie from the classic newborn form to a milder late-onset form to a form without symptoms and/or hyperammonemia to a form in which women have onset of severe symptoms at pregnancy or postpartum. In the classic form, without prompt intervention, hyperammonemia and the accummulation of other toxic metabolites result in increased intracranial pressure, spasticity, seizures, coma and death. Citrullinemia type I results from deficiency of the enzyme argininosuccinate synthase (ASS). Defects in the ASS gene causes citrullinemia type I and the condition is inherited in an autosomal recessive manner.
Familial Mediterranean fever (FMF) is characterized by recurrent short episodes of inflammation, pain and fever. The symptoms and severity vary among affected individuals, sometimes even among members of the same family. Treatment with colchicine helps prevent both the inflammatory attacks and other symtptoms. FMF is an autosommal recessive condition, and more common in individuals of Mediterranean and Armenian ancestry. MEFV is the only gene currently known to be associated with FMF.