What are the genetic changes related to Ochoa syndrome ?
Ochoa syndrome can be caused by mutations in the HPSE2 gene. This gene provides instructions for making a protein called heparanase 2. The function of this protein is not well understood.  Mutations in the HPSE2 gene that cause Ochoa syndrome result in changes in the heparanase 2 protein that likely prevent it from functioning. The connection between HPSE2 gene mutations and the features of Ochoa syndrome are unclear. Because the areas of the brain that control facial expression and urination are in close proximity, some researchers have suggested that the genetic changes may lead to an abnormality in this brain region that may account for the symptoms of Ochoa syndrome. Other researchers believe that a defective heparanase 2 protein may lead to problems with the development of the urinary tract or with muscle function in the face and bladder.  Some people with Ochoa syndrome do not have mutations in the HPSE2 gene. In these individuals, the cause of the disorder is unknown.