Urofacial Syndrome - Cause

Cause

Urofacial Syndrome occurs due to either disruption or mutation of a gene on chromosome 10q23q24. The gene is located on a 1 centimeter interval between D10S1433 and D10S603. Alteration of this gene leads to alteration of facial and urinary developmental fields. This gene is believed to be the HPSE2 gene. The HPSE2 gene is expressed in both the central nervous system as well as the bladder. Heparanase 2 is protein coded by exons 8 and 9 on the HPSE2 gene. This protein is believed to be altered in the case of this syndrome. Studies performed on mice indicate that HPSE2 has no enzymatic activity.

Mutations in the HPSE2 gene on chromosome 10q23q24 have been observed to cause Ochoa Syndrome. This means the defective gene responsible for the disorder is located on an autosome (chromosome 10 is an autosome), and two copies of the defective gene (one inherited from each parent) are required in order to be born with the disorder. The parents of an individual with an autosomal recessive disorder both carry one copy of the defective gene, but usually do not experience any signs or symptoms of the disorder.

The relationship between a defective HPSE2 gene and Ochoa syndrome is unclear. There is postulation that the genetic changes may lead to an abnormality in the brain region, evidence for this postulation is that the areas of the brain that control facial expression and urination are in close proximity of each other. Other hypotheses think that the defective heparanase 2 protein may lead to problems with development of the urinary tract or with muscle function in the face and bladder.