Fucosidosis is an autosomal recessive lysosomal storage disorder due to alpha-l-fucosidase deficiency with widespread accumulation of an array of oligosaccharides and sphingoglycolipids. Different phenotypes can be caused by the same gene mutation. The disorder has been categorized clinically by whether the course is rapidly progressive (type 1) or chronic (type 2). The pace of the progressive clinical course may have a predictive value.

Clinical features

Psychomotor retardation is recognized between 5 and 15 months of age. These children are typically hypotonic and sit at around 9 months of age and walk about 19 months of age (Willems et al., 1991). No further developmental progress is observed for the next few months, then slow loss of previously acquired mental and motor skills may occur. The few words that some children have acquired are lost, and progressive spasticity develops by age 2 to 4 years. Dystonia of the neuroaxis and feet develops (Durand et al., 1967). Seizures occur in a third of the patients.

By age 4 years, children develop fullness of the face reminiscent of patients with the mucolipidoses. In older patients, facial dysmorphism may suggest a glycosaminoglycan storage disease (GAG).

Angiokeratomas (Fig. 27.1) similar to those of Fabry disease occur in fucosidosis. These lesions increase and spread over time; they may appear by age 6 years and are present in a third of 10-year-olds and in most adolescents. Angiokeratomas may be a hallmark of a slowly progressive course, but they may also occur in patients who die early.