Hyperlysinaemia

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Hyperlysinaemia is caused by a problem in the gene that provides information for the production of the enzyme known as aminoadipic semialdehyde synthase (AASS) which is involved in the first two steps of lysine degradation. By having a problem in the gene that produces AASS you will be unable to breakdown lysine which causes a build-up of lysine in the blood and various amounts of saccharopinuria found in the blood and urine. 

Unfortunately, the prevalence of hyperlysinaemia is unknown.  

Hyperlysinaemia manifests itself during infancy and the signs and symptoms of hyperlysinaemia are: 

• Growth inhibition 
• High levels of lysine in the blood and cerebrospinal fluid 
• Various levels of saccharopinuria  
• Abnormality in the genitourinary system 
• Anaemia 
• Cognitive impairment 
• Delayed speech and language development 

Hyperlysinaemia is a disease that can be diagnosed using newborn screening and genetic testing via the genetic testing registry, which will test for hyperlysinaemia and saccharopinuria.  

Which can be tested by analyte, which is the any sample taken from the body such as blood, urine, saliva etc in the biochemical and genetics laboratory in the children’s hospital in Dayton, United States.

It is not yet proven but a low lysine or protein diet may be beneficial to some individuals. 

Every person has two genes that code for aminoadipic semialdehyde synthase. Since hyperlysinaemia is an autosomal recessive metabolic disorder, for a child to inherit it they will need to inherit two copies from their parents.  

One from the mother which comes from the egg and the other from the father which comes from the sperm, which will produce the defective enzyme. The parents do not need to have hyperlysinaemia in order to pass it to their children in this case the father and mother are known as carriers, they have one defective gene and the normal functioning gene. Resulting in the parents not developing hyperlysinaemia.  

When parents are both carriers of the hyperlysinaemia gene: 

• There is a 25% chance that the child will be unaffected and not a carrier of the disease. 
• There is a 25% chance that the child will be affected by hyperlysinaemia and carry both genes  
• There is a 50% chance that they will produce children that are carriers of the disease and have only one hyperlysinaemia gene.

References are available on request. Please contact us on 0800 652 3181 or by emailing contact@metabolicsupport.org.

Please note calls to 0800 numbers are free from UK landlines and mobiles. Calls from business lines may be charged – please check with your provider.

This information about metabolic diseases is provided by Metabolic Support UK and is intended for educational purposes only. It should not be used for diagnostic or treatment purposes.

Should you require more detailed information please contact Metabolic Support UK by email (contact@metabolicsupport.org) or by telephone ( 0800 652 3181). For specific medical information regarding a disorder or individual please contact your GP or Paediatrician. Metabolic Support UK accepts no responsibility for any errors or omissions nor does Metabolic Support UK assume any liability of any kind for the content of any information contained within this summary or any use that you may make of it.