Fucosidosis

Fucosidosis is a rare genetic condition characterized by an inability to properly break down certain sugars attached to specific proteins and fats in the body’s cells. The buildup of these sugars affects many of the body’s organs and systems, including the brain and central nervous system. The severity of the disease can vary significantly. Some people experience severe, rapidly progressive illness while others have relatively mild symptoms. Fucosidosis is one of about 50 diseases classified as lysosomal storage disorders (LSD) in which a genetic variation disrupts the normal activity of lysosomes in human cells.

Lysosomes in human cells contain specific proteins known as enzymes that are responsible for breaking down and recycling molecules such as fats and sugars. Individuals with a lysosomal storage disorder lack one of these necessary enzymes, or do not contain one of these enzymes in sufficient quantities for cells to function properly.

Fucosidosis is caused by mutations in a gene known as FUCA1, which provides instructions for the production of an enzyme called alpha-L-fucosidase. Alpha-L-fucosidase usually works in a cell’s lysosomes and is responsible for the breakdown and recycling of specific complex sugars attached to protein and fat molecules. Genetic mutations in the FUCA1 gene interfere with the ability of alpha-L-fucosidase to perform its function correctly, leading to an accumulation of complex sugar molecules in cells that eventually causes cells to malfunction. This genetic condition is inherited in an autosomal recessive pattern, which means that an affected child has received one defective copy of the FUCA1 gene from each of their parents.

Children with fucosidosis may present with symptoms shortly after birth, or may develop signs later in childhood. Some symptoms they may experience include:

• Intellectual disability
• Delay in motor skills development
• Impaired or slow growth (failure to thrive)
• Abnormal skeletal development (dysostosis multiplex)
• Seizures
• Abnormal muscle contractions (spasticity)
• Distinctive facial features (coarse facial features)
• Recurrent respiratory infections
• Clusters of small, dark red spots on the skin (angiokeratomas)
• Enlargement of some internal organs (visceromegaly)

There are currently no approved therapies that reverse the effects of fucosidosis. Current approaches treat specific symptoms through interdisciplinary collaboration.

At the Boston Children’s Lysosomal Storage Disorder (BoLD) Program, our team of providers is committed to the care of complex patients. As part of Boston Children’s Hospital, we are prepared to meet the challenge of providing multifaceted care by partnering with you and your child to deliver direct care in our BoLD clinic. We work with the broad array of world-class specialists at Boston Children’s to optimize the care we provide your child with fucosidosis.