What else is it called?

  • 4 – HPPD deficiency  
  • 4 – alpha – hydroxyphenylpyruvate hydroxylase deficiency  
  • 4 – hydroxyphenylpyruvic acid dioxygenase deficiency  
  • HAWK 

Get in touch

Contact our caring team on 08452 412 173 for help and support. Our phone lines open 10am-4pm, Monday to Friday.

Prefer to email? Our email address is contact@metabolicsupportuk.org.

What causes it?

Hawkinsinuria is caused by a mutation in the HPD gene that codes for the HPD enzyme which is used to break down tyrosine. Which means that the protein that breaks down tyrosine is made incorrectly which means that it is not a functioning protein. Resulting in the accumulation of Hawkinsinuria and tyrosine.  

How common is it?

Hawkinsinuria is an extremely rare inherited metabolic disorder, it is estimated that the prevalence of Hawkinsinuria is less than 1:1,000,000.

What are the signs and symptoms?

The signs and symptoms of Hawkinsinuria manifest at around 18 weeks of age and becomes more apparent during the time that a baby is being weaned of breast milk and begin being fed milk formula. 

The signs and symptoms of Hawkinsinuria are:  

  • Failure to gain weight and grow (failure to thrive)  
  • Abnormally high acid levels in the blood 
  • Vomiting  
  • Diarrhoea  
  • Fine or sparse hair 
  • Abnormal concentration of tyrosine within the blood 
  • Pretibial oedema  
  • Chlorine like smell in urine  

How is it diagnosed?

Hawkinsinuria is diagnosed using a urine sample, the premise of the urine sample is to detect tyrosine metabolites by organic acid analysis in the urine. 

Can it be treated?

Infants with Hawkinsinuria usually are treated using a phenylalanine and tyrosine restricted diet. However, as the child gets older their bodies begin to develop a tolerance towards these amino acids which means that they will be able to have a normal healthy diet and do not need to be on any special diet and medication.  

Do my family need to be tested?

Hawkinsinuria is an autosomal dominant inherited metabolic disorder. Humans are made up of DNA and DNA is made up of chromosomes. Genes are sections of DNA that provide instructions to the body in order for specific proteins to be made. We inherit particular chromosomes from the egg from the mother and sperm from the father. Every human has two genes that are needed in order to make the protein that breaks down tyrosine. In an autosomal dominant disorder, a child only needs to inherit one of the non-working HPD gene in order for the child to inherit it.  

When one parent has Hawkinsinuria, the chance of the baby getting hawkinsinuria in each pregnancy is as follows: 

  • 50% unaffected if they receive two working genes 
  • 50% affected if they receive at least one fault gene.  

Relevant Organisations


References are available on request. Please contact Helen Morris by phoning 0845 241 2173 or emailing helen@metabolicsupportuk.org [Resource Library No: AAP002]. 

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