Guidance

Homocystinuria (HCU): summary

Updated 18 November 2021

Applies to England

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This publication is available at https://www.gov.uk/government/publications/hcu-suspected-description-in-brief/hcu-suspected

Public Health England (PHE) created this information on behalf of the NHS. In it, the word ‘we’ refers to the NHS service that provides screening.

This information is for parents if their baby is suspected of having HCU or has been diagnosed with HCU following their newborn blood spot screening test (‘heel prick test’). It will help you and your health professionals to talk through the next stages of your baby’s care.

About HCU

Homocystinuria (pronounced ho-mo-sis-tin-ur-ee-a), or HCU, is a rare but treatable inherited metabolic disorder that prevents the normal breakdown of protein. Babies with HCU inherit 2 faulty copies of the gene for HCU, one from each parent.

Untreated HCU can lead to long-term health problems, including visual problems and learning difficulties, but with newborn screening and early treatment this can be prevented.

Screening and diagnosis of HCU

Newborn blood spot (‘heel prick test’)

When your baby was about 5 days old, your midwife took some blood from your baby’s heel for their newborn blood spot screening test (the ‘heel prick test’). The newborn blood spot screening test measures the amount of some amino acids in the blood. A high level of the amino acids methionine and total homocysteine suggests your baby may have HCU. This is called a screen positive result.

Diagnostic tests

If your baby has a screen positive result, you will be seen by a metabolic doctor, dietitian and nurse specialist (the ‘metabolic team’). The team will provide advice and support. Blood tests will be carried out to confirm or exclude the diagnosis of HCU.

You will need to wait a few days for the test results. During this time, you can continue to breastfeed or give normal infant formula.

Treatment

If your baby does have HCU, the metabolic team will explain the condition in more detail and answer any questions you might have. They will start your baby on medical treatment and a special diet, and they will arrange regular follow-up appointments. Following the diet and treatment instructions is very important for your baby’s health.

Confidentiality

The NHS screening programmes use personal information from your NHS records to invite you for screening at the right time. Public Health England also uses your information to ensure you receive high quality care and to improve the screening programmes. Find out more about how your information is used and protected, and your options.

More information and support

The metabolic team will be happy to discuss any queries you might have.

For more information, see Homocystinuria (HCU): further information.

Further information can be found at Metabolic Support UK. The Metabolic Support UK team can be contacted at:

The British Inherited Metabolic Diseases Group (BIMDG) website has a TEMPLE booklet about HCU.

NHS.UK has information about HCU and newborn blood spot screening.

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