GM1-gangliosidosis is a rare neurovisceral storage disease caused by an 
inherited deficiency of acid beta-galactosidase. The characteristic neurological 
feature of type 3 (adult or chronic) GM1-gangliosidosis is usually a slowly 
progressive dystonia with dysarthria due to predominant involvement of basal 
ganglia. About 20 adult patients with this disorder have been reported in the 
literature. However, there are no reports of 3 brothers with type 3 
GM1-gangliosidosis, and MRI findings. Case 1 (proband): A 28-year-old man was 
hospitalized because of facial grimace, dysarthria, and generalized dystonia. He 
was born after normal pregnancy and delivery. His development was normal until 3 
years of age when the difficulties of speaking and walking were noticed by his 
parents. These neurological abnormalities progressed slowly and facial grimace 
and dystonic movements occurred 7 years later. He could not walk at 22 years of 
age. On admission, he was bedridden with marked scoliosis and subluxation of the 
mandibule. The communication was possible only by pointing the words written on 
the board. Case 2: A 33-year-old man, elder brother of case 1, showed the 
similar neurological features and clinical course. Slit-lamp examination 
revealed corneal opacities which were located in the deep stroma. Case 3: A 
33-year-old man, elder brother of case 1 or case 2. At age 10-11, he noted 
similar symptoms as case 1 or case 2. The severity of dystonia was milder than 
his brothers. A diagnosis of GM1-gangliosidosis in three patients was made on 
the basis of the following data.(ABSTRACT TRUNCATED AT 250 WORDS)