HWN Suggests

October is homocystinuria awareness month, also

Symptoms can vary widely among those with HCU, which can make diagnosis a challenge. I am one of the lucky ones. I struggled with many aspects of this disease, including multiple eye issues, wore a back brace for scoliosis, and had a stroke and several blood clots in my lungs. I must have a guardian angel looking over me, because I somehow survived everything before my diagnosis. HCU is now tested as part of newborn screening in all 50 states, but not all cases are caught. Sadly, it’s not uncommon for young children to develop life-threatening complications.

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 Living with Classical Homocystinuria

It starts with the foods you eat. Your body makes homocysteine from another amino acid called methionine (meh-THIGH-uh-neen). Most foods contain some methionine. But high-protein foods such as meat, fish, eggs, or cheese tend to have the most methionine. Plant-based foods such as beans, tofu, and nuts also have higher amounts of methionine. So when you eat these types of foods, more methionine enters your body. Then your body breaks down or metabolizes the methionine you’ve eaten into homocysteine.

Articles of Interest

A revisit to the natural history of homocystinuria due to cystathionine β-synthase deficiency

Homocystinuria was first described in 1962 in a search among mentally retarded individuals, and the discovery of cystathionine β-synthase deficiency as a causative enzymatic deficiency followed shortly thereafter.

Classical Homocystinuria

Cystathionine Beta-Synthase (CBS) deficiency, more commonly referred to as homocystinuria is a rare metabolic condition characterized by an excess of the compound homocysteine in the urine and blood. CBS deficiency is one of the conditions which often result from deficiency of any one of several enzymes involved in the conversion of the essential amino acid methionine to another amino acid (cysteine)–or, less commonly, impaired conversion of the compound homocysteine to methionine.

Current and Novel Therapeutical Approaches of Classical Homocystinuria in Childhood With Special Focus on Enzyme Replacement Therapy, Liver-Directed Therapy and Gene Therapy

Classical homocystinuria is a hereditary defect of the enzyme cystathionine beta synthase, which is produced in the liver. If this enzyme fails, the synthesis pathway of cysteine from methionine is interrupted, leading to the accumulation of homocysteine in the blood plasma and homocysteine in the urine.

Homocystinuria

The first investigations published in PubMed date back to 1963, with 3 articles while, today, more than 80 research articles are published per year, the most recent being on the use of liver transplantation as an effective treatment in patients with classic homocystinuria , or on obsessive-compulsive behaviors in these patients as a pathognomonic manifestation.

Homocystinuria diagnosis and management: it is not all classical

Homocystinuria (HCU) refers to a group of inherited disorders of homocysteine metabolism associated with high blood homocysteine concentration, thromboembolic tendency and neurocognitive symptoms. The most common causes of a high blood homocysteine relate to underlying vitamin B12 or folate deficiency which must be excluded first. Thereafter, an inherited metabolic condition can be considered.

Homocystinuria: Challenges in diagnosis and management

Without a high index of suspicion, physicians can easily overlook a diagnosis of homocystinuria. The management of patients with homocystinuria continues to pose a challenge to physicians and care givers.

Understanding HCU

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. Treatment for HCU depends on the type that is diagnosed.

What is Homocystinuria?

Proteins perform many of the body’s functions and make up its structure. In homocystinuria, an enzyme called cystathionine beta-synthase (CBS) is needed to break down amino acids called methionine and homocysteine. When CBS is missing, these amino acids are not broken down correctly and build up in the body. High homocysteine levels can lead to health problems. Multiple forms of homocystinuria exist.

What to know about homocystinuria

Often abbreviated as HCU or HCY, homocystinuria is a genetic disorder that inhibits the body from processing certain amino acids found in proteins, causing a harmful buildup of homocysteine and methionine.

Resources

HC&U: A Homocystinuria Podcast

HC&U is a podcast about Homocystinuria, sponsored by HCU Network America and hosted by Ben and Linds.

HCU Network America

HCU Network America strives to inform and provide resources for patients and families, create connections, influence state and federal policy, and support advancement of diagnosis and treatment for HCU and related disorders.

Cystadane

CYSTADANE (betaine anhydrous for oral solution) is indicated in children and adults for the treatment of homocystinuria to decrease high homocysteine blood levels. Homocystinuria is a rare genetic disorder in which there is an abnormal accumulation of the amino acid homocysteine in the blood and urine.

HCU Network Australia

HCU Network Australia is a Health Promotion Charity established in 2014, with the vision “to be a driving force in the journey to a cure, improving quality of life along the way”.

NIH

Homocystinuria refers to a group of inherited disorders in which the body is unable to process certain building blocks of proteins (amino acids) properly. This leads to increased amounts of homocysteine and other amnio acids in the blood and urine. The most common type of genetic Homocystinuria, called CBS deficiency, is caused by the lack of an enzyme known as cystathionine beta-synthase (CBS). Most states in the United States test for Homocystinuria due to CBS deficiency at birth by newborn screening.

Radiopaedia

A deficiency of the enzyme cystathionine-β-synthase causes classic homocystinuria whereby the metabolism of homocysteine to methionine is affected. It is inherited in a autosomal recessive fashion. Other forms of secondary homocystinuria can be seen in other rare inborn metabolism disorders (e.g. methylenetetrahydrofolate reductase deficiency).