Understanding HCU

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Nov 30, 2020 | Health Information

Today’s Solace Nutrition blog post would like to share with you some of the basics of this rare disease.

Homocystinuria (HCU), is a rare genetic disease. It is also referred to as cystathionine beta-synthase (CBS) deficiency. It involves the metabolism of the essential amino acid methionine, which is necessary for human growth and nitrogen balance. It is also characterized by a deficiency in any of a number of enzymes that play a role in converting methionine to cysteine. It is also associated with insufficient vitamin B12 (cobalamin) synthesis, an effect of defective reconversion of homocysteine to methionine.There are two types of HCU, classical and non-B6 responsive Homocystinuria. This disease affects at least 1 in 200,000 people worldwide.1

Symptoms of HCU include eye issues such as short-sightedness and lens dislocation, skeletal issues that include scoliosis and a tall stature, neurological issues such as seizures and developmental disabilities, and blood clots. The disease is diagnosed by pricking the heel of the person’s foot to draw blood. With this blood sample, doctors are looking for elevated levels of homocysteine.2

Treatment for HCU depends on the type that is diagnosed. Classical HCU can be treated with high-dose Vitamin B6 supplementation. This may be all the patient needs, while others require further treatment. B6 non-responsive patients require adopting a low protein diet and treatment of medical formula, betaine (if homocysteine levels are above the targets goals), and folic acid. B12 supplementation may also be utilized.3 Many patients will need to have their blood regularly monitored to check homocysteine levels.4 

Why is HCU Awareness important? 

Being a “rare” disease does not diminish the impact on the lives of those with it or close to someone with it. The goal is not just to raise awareness of the disease itself, but to also shed light on how it affects the lives of those dealing with it. Those diagnosed with HCU, or any rare disease, are faced with unique challenges that can oftentimes be difficult to understand from an outsider’s perspective. Lack of awareness leads to stigma. For example, if a child’s friend group discovers they have HCU and requires a specialized diet, they may not be invited to birthday parties. This is not because they are intentionally leaving them out, but they may just want to avoid any food mishaps. In reality, all it takes is a few low-protein treats to be offered as an option. 


Tips for patients and caregivers

HCU is a life-threatening disease. When not properly treated, it can lead to fatal blood clots and strokes. Above all else, it is important for patients to listen to their doctors and to be proactive when treating this disease. It can be tiring, however, many may find comfort in knowing they are not alone.

There are many resources and networks for caregivers and patients to explore. Still, at times, it can feel overwhelming. Here’s a list of support websites that provide further information on the disease itself, patient experiences, treatment options and food recipes that are HCU-friendly. 

There is also an HCU Support Facebook page where you can easily connect with others with HCU. These groups are often valuable in sharing clinical research updates as well. 

HCU Network America: www.hcunetworkamerica.org/about-us/  

HCU Network Australia: www.hcunetworkaustralia.org.au/about 

Metabolic Dietary Disorders Association: www.mdda.org.au/diagnosis/hcu/

HCU Support: www.hcusupport.com 

There are many decisions to be made and factors to be considered. However, medical teams are equipped to assist caregivers with knowledge and proper assistance. Staying in close contact with the medical team that is overseeing the patient’s case is key to keeping further complications of HCU from arising. Before trying anything, consult your doctor beforehand as they have the most comprehensive knowledge of the patient’s case. 

How we can help

At Solace Nutrition, we provide medical foods for those with HCU. Our product VB6 P5P is a concentrated vitamin B6 powder medical food designed especially for those with Classical HCU. VB12 MAX may also be used in the dietary management of non-B6 responsive disorders. 

VB6 P5P is a concentrated and active form of Vitamin B6 powder. P5P stands for the soluble and highly bioavailable form of Vitamin B6 powder as Pyridoxal 5-Phosphate. It can be consumed either orally or through a feeding tube, and is free of GMO, artificial flavorings and preservatives. As always, our goal is to provide high-quality medical foods that provide patients with the support they need. 

We would love to hear from you! Share a story about your daily life with HCU with us. What is something you wish people understood about HCU? What is the most challenging part of living with this disease? Send your story to info@solacenutrition.com


  • Hcunetworkaustralia.org.au. n.d. What Is Homocystinuria? | HCU. [online] Available at: <https://www.hcunetworkaustralia.org.au/hcu/hcu-info/> [Accessed 27 October 2020].
  • 2017. What Is HCU?. [ebook] HCU Network Australia. Available at: <http://www.hcunetworkaustralia.org.au/wp-content/uploads/2017/02/HCU-infographic.pdf> [Accessed 27 October 2020].
  • Hcunetworkamerica.org. n.d. Step 4: What Treatments Are Available? – HCU Network America. [online] Available at: <https://hcunetworkamerica.org/step-4-what-treatments-are-available/> [Accessed 27 October 2020].

2020. Homocystinuria Handbook. [ebook] National Centre for Inherited Metabolic Diseases, p.33. Available at: <http://metabolic.ie/wp-content/uploads/2015/05/HCU-Handbook.pdf> [Accessed 27 October 2020].