Argininosuccinic aciduria

Argininosuccinic aciduria can be very severe right from birth, or there may be forms of the disorder that do not develop until after infancy. When the disorder occurs at birth or during infancy the disorder can be severe and may cause life-threatening problems. Infants may not eat well, may vomit, have irregular heartbeats, and be very tired (lethargic). The can also develop fluid around the brain or seizures. Their livers may be very large. They can have irregular heartbeats and low body temperature. Other problems may develop including liver damage and, although uncommon, kidney disease. They may have dry, brittle hair that falls out or breaks easily. If untreated, the disorder will worsen. This called a metabolic crisis and occurs because of highly elevated ammonia levels. Infants will become more lethargic, refuse to eat, can develop seizures, and may fall into coma. A metabolic crisis is a life-threatening complication that can be fatal. As infants and children age, they may also experience delays in reaching developmental milestones like sitting up or crawling and have intellectual disability.

When symptoms develop outside of the newborn period, this is called a late-onset form. The late-onset forms may have metabolic episodes similar to that seen in infants. These episodes usually happen after an infection, stress, when a child does eat a lot for a long time, or when a child eats or drinks a lot of protein. Some children with late-onset forms develop intellectual disability, learning disabilities, seizures, and behavioral issues without any metabolic episodes. High blood pressure is very common in people with argininosuccinic aciduria as well.

Argininosuccinic aciduria is highly variable. This means how the disorder affects one person can be very different from how it affects another. Some people do not develop any symptoms; they are known as asymptomatic. Others have very severe problems during infancy.