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Citrullinemia Type 1 (CTLN 1)

What is CTLN 1?

Citrullinemia type 1 (CTNL 1) is a rare inherited condition characterized by the accumulation of ammonia and other toxins in the blood stream. This disease is most often apparent shortly after birth.  Occasionally, symptoms of CTNL 1 can develop later in childhood and even in adulthood. It is estimated that the most common form of CTNL 1 occurs in 1 in 57,000 people worldwide.

What are the symptoms of CTNL 1?

The severity of the symptoms of CTNL 1 varies from person to person. The symptoms of the most common form of CTNL 1 occur shortly after birth.  These infants can experience the following symptoms:
  • Lethargy
  • Poor feeding
  • Vomiting
  • Seizures
  • Stroke
  • Enlarged liver
  • Loss of consciousness
  • Increased pressure in the brain
  • Coma
  • Death if not treated
In the less common later childhood onset CTNL 1 symptoms include:
  • Failure to grow or gain weight normally (Failure To Thrive)
  • Poor muscle control and coordination (Ataxia)
  • Lethargy
  • Vomiting
  • Intense headaches
  • Vision problems
Adult onset symptoms of CTNL 1 are found during or after pregnancy and include:
  • Vomiting
  • Lethargy
  • Seizures
  • Hallucinations
  • Behavioral changes such as aggression and psychosis
  • Fluid accumulation around the brain
  • Coma

What causes CTNL 1?

CTNL 1 is caused by an inherited genetic defect.  This defect must be inherited from the mother and the father. A person who has the genetic defect but not the disease is known as a carrier. The defect that is inherited causes ineffective production of argininosuccinate (ASS) enzyme.  This enzyme is responsible for the proper elimination of ammonia from the body and other toxins through the urine. This inability for the necessary elimination of these toxins leads to a buildup in the blood.

Are there treatment options for CTNL 1?

The treatment of CTNL 1 is directed at symptom control and complication management by regulating the amount of ammonia in the blood.  These treatments include:
  • Medications such as Buphenyl, Ammoul, Raviciti and Arginine which help remove ammonia producing nitrogen from the body.
  • Dietary restrictions such as a low protein, high calorie diet
  • Administration of amino acids to help supplement the dietary protein restriction
  • Multi-vitamin and calcium supplements
  • Medications for vomiting
  • In severe cases, filtering of the blood toxins known as hemodialysis
  • Close monitoring of brain pressures
  • Liver transplant

Where can I find more information on CTNL 1?

Citrullinemia Type 1 Articles