Juvenile galactosialidosis with attacks of neuropathic pain and absence of sialyloligosacchariduria.

Galactosialidosis (MIM 256540) is an autosomal recessive lysosomal storage disease caused by a defect of the protective protein/cathepsin A. Increased amounts of urinary sialic acid-rich oligosaccharides are considered to be an essential diagnostic marker of the disease. We here report a patient with atypical clinical features who consistently has excreted normal amounts of sialyloligosaccharides in the urine. The boy started to have attacks of neuropathic pain associated with hyperesthesia around 1½ years of age. From 4 years of age when his vision was first tested, the patient developed progressive visual loss and at the age of 10 years, macular cherry-red spots were found. At this age, he also had a mild learning disability and clinical examination showed mild facial coarsening, increased lumbar lordosis and pyramidal signs in the legs. In conclusion, the clinical and laboratory features of this patient show that galactosialidosis may be considered in patients even in the absence of oligosacchariduria and that galactosialidosis should be regarded as a differential diagnosis in patients with neuropathic pain.