Myoclonus and angiokeratomas in adult galactosialidosis

Abstract

Galactosialidosis is an autosomal recessive lysosomal storage disorder characterized by a combined deficiency of b- galactosidase and a-neuraminidase, due to a defect of another lysosomal protein, cathepsin A. The latter, forms a complex with b-galactosidase and neuraminidase, and protects them against excessive proteolytic degradation. Three clinical phe- notypes had been described: a severe early infantile form; a milder late infantile type with minor mental deterioration; and a juvenile/adult form, mainly found in Japan, which is characterized by slowly progressive neurological symptoms, skeletal and eye abnormalities, dysmorphism, angiokerato- mas, and long survival.1 Herein, we report a case of galacto- sialidosis of the juvenile-adult form in a Peruvian girl with angiokeratoma corporis diffusum (ACD) and myoclonus. A 24-year-old woman presented a 5-year history of invol- untary movements. At age 19, she developed a progressive myoclonic disorder that started in the lower limbs and caused frequent falls. The myoclonus subsequently spreads to other body regions. Five years into the disease, she was almost wheelchair bound, and other activities such as eating and speaking were considerably affected. There were, how- ever, no seizures or cognitive decline.Physical examination revealed densely peppered red mac- ules ranging from 1 to 3 mm on palms, elbows, knees, oral mucosa, lips, and on thighs and loins in a bath- ing suit distribution. Biochemical analysis showed elevated urinary sialyloligosaccharides char- 1 acteristic for galactosialidosis.