Symptoms of ASL Deficiency

When there is the presence of ammonia inside our body, ammonia would be converted into a substance called 'urea'. Urea is removed via urinating. Ammonia is very harmful to our body. It would build up in our blood if it is not changed to urea. With high levels of ammonia, serious brain damage can happen.

Different people develop symptoms and different stages. There are 2 main forms of Argininosuccinate Lysase deficiency. The most common form happens shortly after birth. The milder form happens late in infancy or early childhood.

ASAL deficiency in newborns
Infants might be healthy at birth but within a few days of life, symptoms can be developed quickly. Some of the first symptoms of high blood ammonia are:

• poor appetite
• excess sleepiness or lack of energy
• irritability
• vomiting

If not treated, high ammonia levels can cause:

• muscle weakness
• decreased or increased muscle tone
• breathing problems
• problems staying warm
• seizures
• swelling of the brain
• coma, and sometimes death

Other effects of ASAL deficiency can include:

• poor growth
• enlarged liver
• delays in learning or intellectual disability

Without treatment, many babies die within the first few weeks of life.

ASAL deficiency in childhood
In this milder form, symptoms start later in infancy or childhood. Some common symptoms in children who are not treated are:

• poor growth
• dry, brittle hair
• hyperactivity
• behavior problems
• learning disabilities or intellectual disability
• avoidance of meat and other high protein foods
• enlarged liver
• small head size
• episodes of excess ammonia in the blood

Episodes of high blood ammonia often happen:

• after long periods of going without food
• during illness or infection
• after high-protein meals

In children, some of the first symptoms of high blood ammonia are:

• poor appetite
• intense headache
• vomiting
• extreme sleepiness or lack of energy
• slurred speech
• poor coordination and balance problems

If not treated, children with high blood ammonia levels can develop:

• breathing problems
• swelling of the brain
• seizures
• coma, sometimes leading to death

Some people have very mild symptoms and are only found to be affected after a brother or sister is diagnosed.