What is Homocystinuria?

The disease

Homocystinuria is an autosomal recessively inherited disorder. This means that an individual inherits the same defective gene for the same trait from each parent.


Homocystinuria is a metabolic disease affecting the trans-sulfuration pathway or methylation pathway.  Classical Homocystinuria, the most common form of Homocystinuria, is caused by a deficiency in the enzyme known as Cystathionine Beta-Synthase (CbS).  The lack of the enzyme prevents the body from processing methionine, an essential amino acid, from food containing protein.  As a result toxic levels of harmful substances accumulate in the body and cause serious health problems.

There are multiple forms of Homocystinuria, each distinguished by their clinical signs and symptoms and underlying genetic basis.

Classical Homocystinuria affects at least 1 in 200,000 to 335,000 people worldwide.  The incidence of the rarer forms of Homocystinuria are unknown.

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The symptoms

Homocystinuria is progressive and affected individuals suffer multi-systemic disorder of the central nervous system (CNS), ocular, skeletal, and cardiovascular system.  Symptoms are highly variable but include intellectual disability, developmental delay and learning difficulties, psychiatric disturbances, behavioural problems, dislocation of the lens of the eye resulting in blindness if untreated, seizures, osteoporosis and skeletal abnormalities, premature heart attack and stroke.  As a whole, the complications of the disease lead to a reduced quality of life and significantly shorter life expectancy.

The treatments

No cure has been discovered for Homocystinuria.  However, nearly one half of individuals affected with Homocystinuria benefit from Vitamin B6 supplementation.  For the remainder, the current mainstay of treatment is a strict low protein diet coupled with supplementation with B6, B12, folate, and Betaine together with a ‘medical formula’.  This treatment regime aides in the restoration of metabolic balance in the affected individual.

Focus of treatment in the newborn period is to ensure the development of normal intelligence and the prevention of the development of other complications of the disease.  When treatment is commenced later, the aim is to prevent further escalation of the complications already present.

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HCU in the media


Press Release: Rare Disease Day Prague 2016

The Recordati Rare Disease Foundation supports the 1st Patient & Expert Meet in Prague on Rare Disease Day, 29th February 2016. The Patient & Expert Meet will bring together key stakeholders, such as patients, clinicians and researchers, from across the world to help increase awareness and improve education about homocystinuria, methylation defects and folate defects.…

Serving diet help

Most people with the disease can’t eat meat, dairy, bread or fish, but their little bodies need protein to grow. – Tara Morrison MOST parents keep an eye on what their children eat. Picture: CARMELA ROCHE Connor, 6, and Lincoln, 2, with mum Tara Morrison.But when your two boys could die if they eat meat,…

Runners step up fight against infant disorder

WHEN Castle Hill’s Tara Morrison and her team of runners start the 9km course in the Sydney Running Festival, it will be a significant moment for the group. Picture: PETER KELLY Tara Morrison trains for the running festival. Mrs Morrison and her husband Ryan started their charity HCU Network Australia a couple of months ago,…

Faces of hope. Stories of hope.

Submit a story

Regardless of whether you are an individual affected by HCU, a carer, family member, friend or volunteer we would love you to share your story. Sharing your story helps to strengthen the HCU community and to share experiences. Share your story today and make a difference.

By submitting this form you give consent for HCU Network Australia to use this story and imagery on its website and for marketing purposes

Clinics in Australia

South Brisbane
North Adelaide


Children’s Metabolic Clinic
The Children’s Hospital, Westmead
Hawkesbury Rd & Hainsworth St, Westmead, Sydney, NSW
ph. (02) 98452525

Adult Metabolic Clinic
Westmead Hospital
Cnr Darcy Rd & Bridge St, Westmead, NSW 2145
ph. (02)98459780


Children’s Metabolic Clinic
Women’s and Children’s Hospital
72 King William Rd, North Adelaide SA
ph. (08) 8161 7295

Adult Metabolic Clinic
Royal Adelaide Hospital
North Terrace, Adelaide SA
ph. (08) 8222 5174


Children’s Metabolic Clinic
Royal Children’s Hospital
50 Flemington Road, Parkville VIC
ph. (03) 9345 6180

Adult Metabolic Clinic
Royal Melbourne Hospital
300 Grattan St, Parkville VIC
ph. (03) 9342 7074


Children’s Metabolic Clinic
Princess Margaret Hospital
Roberts Rd,
Subiaco WA
ph. (08) 9340 8222

Adult Metabolic Clinic
Royal Perth Hospital
Perth WA
ph. 1300 855 275


Children’s and Adult Metabolic Clinic
Lady Cilento Children’s Hospital
501 Stanley Street, South Brisbane QLD
ph. (07) 3068 1111


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We are delighted that our HCU patient diagnosis bags have now been distributed to the Australian clinics for current and newly diagnosed patients.

A diagnosis of a rare disease can change a family’s life. This initiative seeks to provide practical support to alleviate some of the emotional stress and isolation experienced by the individual and their families at the time of diagnosis.

We invite you to take a look inside the HCU Bag. It contains:

· HCU Network Australia brochure

A brochure designed to give general information about Homocystinuria and HCU Network Australia aims and objectives.

· AccuGo Smartphone App brochure

The brochure illustrates the features and functionality of AccuGo for HCU. AccuGo is designed to ease the day to day management of the low protein diet and is a service provided by HCU Network Australia.

· Postcard inviting patients to register online

This postcard is designed to increase the visibility of the organisation and invite individuals to register their contact email to be kept updated of the latest news and events.

· HCU Network Australia portfolio

Overtime patients and/or parents accumulate extensive medical letters, reports and results. The portfolio is designed to collate all of the documentation so that it is at hand when needed. Tabs include blood results, reports, metabolic correspondence, specialist correspondence and notes.

· HCU Network Australia branded soft plush ‘Hugo’ the rare rhino

For the younger patients our branded soft plush rhino is included for comfort.

Healthcare professionals