What biological cycle does HHH syndrome affect?

Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is a disorder of the urea cycle and ornithine degradation pathway. Clinical manifestations and age of onset vary among individuals even in the same family. Neonatal onset (~8% of affected individuals).

How is HHH test done?

Follow-up testing will involve checking your baby’s urine and blood samples for signs of HHH. Harmful amounts of certain substances build up in the body when a child has an amino acid condition, so measuring the amounts of these substances in your baby’s body can help doctors determine if your baby has the condition.

Is HHH syndrome more dominant in males or females?

Based on the few available large series studies on UCDs, HHH syndrome accounts for 1% – 3,8% of all UCDs [62,63]. On the basis of the available information in the literature for 97 out of 111 patients [5-61] the male/female ratio is approximately 2:1 (Table 1).

What is Hyperornithinemia hyperammonemia Homocitrullinuria syndrome SLC25A15?

SLC25A15: hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome. HHH syndrome, also referred to as ornithine translocase deficiency, is an autosomal recessive disorder that affects the urea cycle. The disorder is characterized by accumulation of ammonia in the blood.

How common is urea cycle disorder?

UCDs affect about 1 in 35,000 newborns. There are eight types. They’re named after what’s missing from the urea cycle.

What is OTC disease?

Ornithine transcarbamylase (OTC) deficiency is a rare X-linked genetic disorder characterized by complete or partial lack of the enzyme ornithine transcarbamylase (OTC). OTC is one of six enzymes that play a role in the break down and removal of nitrogen the body, a process known as the urea cycle.

What are some treatments for urea cycle disorders?

A liver transplant can reverse the symptoms of a urea cycle disorder….Treatment

  • Dialysis to remove ammonia from their blood.
  • Feeding them supplements of sugars, fats, and amino acids.
  • Medicines to remove extra nitrogen.

How does urea affect the brain?

According to a latest study, the build-up of urea in the brain to toxic levels can lead to brain damage and eventually dementia. Scientists have discovered a major cause of dementia- a neurodegenerative disease which is marked by memory disorders, personality changes, and impaired reasoning.

Why is there respiratory alkalosis in hyperammonemia?

Hyperammonemia with respiratory alkalosis is caused by a urea cycle defect or transient hyperammonemia of the newborn. Plasma citrulline level can help to localize the defect within the urea cycle. In AS deficiency (ie, citrullinemia), plasma citrulline level is very high (>1000 µmol/L).

What is the pathophysiology of HHH syndrome?

HHH syndrome is an inherited urea cycle disorder caused by deficiency of the mitochondrial 1 ornithine transporter (ORNT1) transferring ornithine from the cytosol to hepatic mitochondria for the ornithine transcarbamylase reaction. Ammonia is detoxified through its conversion to urea by the enzymes in the small boxes.

What is the long-term management of HHH syndrome?

Long-term management of HHH syndrome. Long-term management of HHH syndrome relies on the goals of preventing recurrent hyperammonemia and neurologic sequelae and improving quality of life by the following principles (Haberle; 2012; 30 ): Table 3. Long-Term Medication for HHH Syndrome****

What is the age of onset of symptoms in HHH syndrome?

The onset of symptoms in HHH syndrome ranges from the neonatal period (28 days or younger) to late adolescence/adulthood (older than 12 years). A review showed that early onset of symptoms (before 28 days of age; 22%) is less frequent than late onset (more than 28 days of age; 78%).

What is hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome?

Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome in adulthood: a rare recognizable condition. Neurol Sci 2013;34 (9):1699-701.