What else is it called?

  • Alpha-L-fucosidase deficiency

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?

The FUCA1 gene, responsible for making the alpha-L-fucosidase enzyme, is mutated in Fucosidosis. When this gene is mutated, the enzyme cannot break down sugars, which accumulate and cause cells to malfunction and die.

How common is it?

This is a rare condition affecting fewer than 100 people. It is most common in those with Italian ancestry.

What are the signs and symptoms?

A progressive condition primarily affecting the brain, those with Fucosidosis have worsening intellectual disability and typically develop dementia later in life. The most severe cases begin in infancy and result in death in late childhood. Milder cases see symptoms develop between the ages of 1 and 2 – these individuals may live until mid-adulthood.

Development of motor skills including the ability to walk is slow – any skills learned will deteriorate over time. Growth is impaired, while seizures, spasticity and respiratory infections are common. Spasticity is a state of increased tone of a muscle (and an increase in the deep tendon reflexes). For example, with spasticity of the legs (spastic paraplegia) there is an increase in tone of the leg muscles, so they feel tight and rigid and the knee jerk reflex is exaggerated.

Distinctively coarse facial features can be recognised, including thickened lips and tongue, a broad nose with flattened bridge, a protruding forehead and large, low set ears. Bone development is abnormal and angiokeratomas (small dark red spots caused by enlarged blood vessels) are common. Those with Fucosidosis may have visceromegaly (abnormally large abdominal organs).

How is it diagnosed?

Initial diagnosis may be suspected with the symptoms present. A range of specialised blood and urine tests, biopsies and scans will also help to determine this. Diagnosis is confirmed by a genetic test.

Once the genetic tests have confirmed the diagnosis, immediate family members should be offered genetic testing.

Can it be treated?

There is no cure for Fucosidosis. Treatment is currently based on the individual symptoms which are present and providing support for your child and your family as a whole. A range of therapies such as physiotherapy, massage, and hydrotherapy can help to alleviate some symptoms.

It is important to be aware that specialist anaesthetic guidelines must be followed should your child need to be anaesthetised.

Fucosidosis is a progressive disorder which affects each individual differently. The life expectancy depends on the severity, the more severe cases are fatal within ten years and the less severe cases which progress slower, are often fatal within twenty years.

Do my family need to be tested?

Humans have chromosomes composed of DNA. Genes are pieces of DNA that carry the genetic instruction. Each chromosome may have several thousand genes.

The word mutation means a change or error in the genetic instruction.

We inherit particular chromosomes from the egg of the mother and sperm of the father. The genes on those chromosomes carry the instruction that determines characteristics, which are a combination of the parents.

This is an inherited condition. There is nothing that could have been done to prevent your baby from having Fucosidosis.

Everyone has a pair of genes that make the alpha-L-fucosidase enzyme. In children with Fucosidosis, neither of these genes works correctly. These children inherit one non-working gene from each parent.

Parents of children with Fucosidosis are carriers of the condition. Carriers do not have Fucosidosis because the other gene of this pair is working correctly.

When both parents are carriers, in each pregnancy the risk to the baby is as follows:

  • There is a 25% chance (1 in 4) of the baby having Fucosidosis.
  • There is a 50% chance (1 in 2) for the baby to be a carrier of Fucosidosis
  • There is a 25% chance (1 in 4) for the baby to have two working genes and neither have Fucosidosis or be a carrier

Diagram showing the autosomal recessive inheritance pattern.

Relevant Organisations

Thank you to Alex TLC and the MPS Society for helping provide this up-to-date information.

Established in 2004, Alex TLC provides support and information for all those affected by leukodystrophy. They are also an internationally recognised centre of excellence for those affected with adrenoleukodystrophy and adrenomyeloneuropathy.

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Founded in 1982, the MPS Society has provided support to families affected by MPS, Fabry and related lysosomal diseases in the UK. They do so offering support for those newly diagnosed through to adulthood and beyond, by funding and collaborating on world-class research, raising awareness of these conditions in order to achieve the fastest possible diagnosis, and championing new and existing therapies.

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References are available on request. Please contact Helen Morris by phoning 0845 241 2173 or emailing contact@metabolicsupportuk.org [Resource Library No: FLY028].

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