β-galactosidase deficiency: Prolonged survival in three patients following early central nervous system deterioration

Three adult patients from two families have shown slowly progressive neurologic deterioration since the age of 3 years, associated with profound beta-galactosidase deficiency. Although affected individuals from the two different families differ in degree of intellectual deficit, facial coarseness and spondyloepiphyseal dysplasia, all lack visceromegaly and macular red spots. The diversity of phenotypic expression in these patients and others previously reported suggests the existence of composite genotypes (compound and double heterozygosity).