A very rare inherited metabolic disorder involving high levels of proline in the urine due to a deficiency of the enzyme delta-pyrrolidine 5-carboxylate acid dehydrogenase. Blood proline levels are higher than for hyperprolinemia type I.
* Neurological symptoms * Asymptomatic * Very high blood proline levels
Hyperprolinemia type II is caused by a mutation in the ALDH4A1 gene, for the enzyme pyrroline-5-carboxylate dehydrogenase. This enzyme helps to break down the pyrroline-5-carboxylate produced in the previous reaction, converting it to the amino acid glutamine. The conversion between proline and glutamine, and the reverse reaction controlled by different enzymes, are important factors required to maintain proper metabolism and protein production.