BioSample

Infantile onset;normal size (3.6 kb) and amount of mRNA for GAA;GAA protein detected by antibody;but deficient acid-alpha-1;4 glucosidase (0.35%);hypotonia;donor subject is a compound heterozygote with only one allele expressed: allele one carries a A>G transition at nucleotide 1555 (1555A>G) in exon 11 which results in a substitution of valine for methionine at codon 519 Met519Val (M519V);allele two (the silent allele) contains a G>A transition at the first nucleotide of intron 8 (IVS8+1G>A) of the GAA gene which results in a splicing defect at the 5 donor site;this rare allele was also found in GM12932 and 18 polymorphisms in the GAA gene were identical in both lines suggesting common ancestry (Raben et al. Hum. Mutat. 13:83-84 (1999) .