Gaucher disease results, in most patients, from mutations in the gene encoding 
glucocerebrosidase. Mutation D409H is the third most frequent in Spanish 
patients, accounting for 5.7% of all mutated alleles. This allele is associated 
mainly with the neurological forms of the disease. Recently, homozygosity for 
the D409H mutation has been associated with a particular phenotype, including 
specific cardiovascular symptoms. Here we report a second Spanish patient 
bearing the D409H/D409H genotype with a very early manifestation of the disease. 
The patient started enzyme replacement therapy at 3 months of age. A common 
origin for the Spanish D409H alleles was ruled out by haplotype analysis using 
an internal polymorphism of the glucocerebrosidase gene and two external 
microsatellite markers.