What are the genetic changes related to hyperprolinemia ?
Mutations in the ALDH4A1 and PRODH genes cause hyperprolinemia.  Inherited hyperprolinemia is caused by deficiencies in the enzymes that break down (degrade) proline. Hyperprolinemia type I is caused by a mutation in the PRODH gene, which provides instructions for producing the enzyme proline oxidase. This enzyme begins the process of degrading proline by starting the reaction that converts it to pyrroline-5-carboxylate.  Hyperprolinemia type II is caused by a mutation in the ALDH4A1 gene, which provides instructions for producing 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 glutamate. The conversion between proline and glutamate, and the reverse reaction controlled by different enzymes, are important in maintaining a supply of the amino acids needed for protein production, and for energy transfer within the cell.  A deficiency of either proline oxidase or pyrroline-5-carboxylate dehydrogenase results in a buildup of proline in the body. A deficiency of the latter enzyme leads to higher levels of proline and a buildup of the intermediate breakdown product pyrroline-5-carboxylate, causing the signs and symptoms of hyperprolinemia type II.