Ochoa syndrome is a disorder characterized by urinary problems and unusual facial expressions.

The urinary problems associated with Ochoa syndrome typically become apparent in early childhood or adolescence. People with this disorder may have difficulty controlling the flow of urine (incontinence), which can lead to bedwetting. Individuals with Ochoa syndrome may be unable to completely empty the bladder, often resulting in vesicoureteral reflux, a condition in which urine backs up into the ducts that normally carry it from each kidney to the bladder (the ureters). Urine may also accumulate in the kidneys (hydronephrosis). Vesicoureteral reflux and hydronephrosis can lead to frequent infections of the urinary tract and kidney inflammation (pyelonephritis), causing damage that may eventually result in kidney failure.

Individuals with Ochoa syndrome also exhibit a characteristic frown-like facial grimace when they try to smile or laugh, often described as inversion of facial expression. While this feature may appear earlier than the urinary tract symptoms, perhaps as early as an infant begins to smile, it is often not brought to medical attention.

Approximately two-thirds of individuals with Ochoa syndrome also experience problems with bowel function, such as constipation, loss of bowel control, or muscle spasms of the anus.

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.

Normal Function

The HPSE2 gene provides instructions for making a protein called heparanase 2. Little is known about this protein, but its structure is similar to that of another protein called heparanase 1. Heparanase 1 is an enzyme that splits (cleaves) molecules called heparan sulfate proteoglycans (HSPGs) by removing the heparan sulfate portion (the side chain).

HSPGs are important parts of the lattice of proteins and other molecules outside the cell (extracellular matrix) and of basement membranes, which are thin, sheet-like structures that separate and support cells in many tissues. Cleavage of HSPGs by heparanase 1 may lead to changes in the basement membrane or extracellular matrix that allow cell movement or release of substances from the cell. The specific function of the heparanase 2 enzyme is not well understood, but studies suggest that it may block the action of heparanase 1.

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Ochoa syndrome

At least nine HPSE2 gene mutations have been identified in people with Ochoa syndrome (also called urofacial syndrome), a disorder that causes urinary problems and unusual facial expressions. These mutations 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.

Other Names for This Gene

• heparanase 2
• heparanase-2
• HPA2
• HPR2
• HPSE2_HUMAN

Genomic Location

Ochoa syndrome is inherited in an autosomal recessive pattern. All individuals inherit two copies of each gene. Autosomal means the gene is found on one of the numbered chromosomes found in both sexes. Recessive means that both copies of the responsible gene must be altered to have the condition.

People with autosomal recessive conditions inherit one alteration from each of their parents. The parents, who each have one gene alteration, are known as carriers. Carriers of an autosomal recessive condition typically do not have any signs or symptoms (they are unaffected). When two carriers of an autosomal recessive condition have children, there is a 25% (1 in 4) chance to have a child with the condition.

The following list includes the most common signs and symptoms in people with Ochoa syndrome. These features may be different from person to person. Some people may have more symptoms than others and symptoms can range from mild to severe. This list does not include every symptom or feature that has been described in this condition.

Signs and symptoms may include:

• Bladder that does not work correctly
• Abnormal facial expression
• Constipation
• Incomplete closure of the eyes at night

Facial features may be present in infancy. The urinary tract symptoms may start in childhood or early adolescence. These may include incomplete emptying of the bladder, frequent bladder infections, and the inability to control the bladder. Urine can back up into the kidneys. In some people, these symptoms lead to eventual kidney failure.

• Urologist
• Nephrologist
• Ophthalmologist
• Surgeon
• Dietitian

Ochoa syndrome is a rare disorder. About 150 cases have been reported in the medical literature.