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What is N-acetylglutamate Synthase Deficiency?

N-acetylglutamate Synthase Deficiency is an autosomal recessive disorder that causes an abnormal buildup of nitrogen, in the form of ammonia, in the blood. Too much ammonia is toxic to the body and causes damage to the brain and nervous system. If the condition is not treated, signs and symptoms often appear early in infancy.  Symptoms include lethargy, feeding and breathing problems, inability to control body temperature, seizures, abnormal movements, and, sometimes, coma.  If left untreated, the condition can lead to developmental delays and intellectual disability.  Some people with this condition have symptoms, often triggered by stress or illness, which do not begin until later in life.  People with the later-onset form have repeated episodes that may include vomiting, confusion, problems with coordination, or coma.  Treatment is needed to prevent or reduce symptoms and includes both a special low protein medical diet and medications to reduce the amount of nitrogen in the body. 

What causes N-acetylglutamate Synthase Deficiency?

N-acetylglutamate Synthase Deficiency is caused by a gene change, or mutation, in both copies of the NAGS gene pair.  These mutations cause the genes to not work properly or not work at all.  The NAGS genes make an enzyme that helps the body get rid of excess nitrogen.  When both copies of the NAGS gene pair do not work correctly, ammonia builds up in the body and leads to the symptoms described above. 

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