We have calculated the relative frequency and the birth prevalence of lysos
omal storage diseases (LSDs) in The Netherlands based on all 963 enzymatica
lly confirmed cases diagnosed during the period 1970-1996. The combined bir
th prevalence for all LSDs is 14 per 100,000 live births. Glycogenosis type
II is the most frequent LSD with a birth prevalence of 2.0 per 100,000 liv
e births, representing 17% of all diagnosed cases. Within the group of lipi
doses, metachromatic leukodystrophy (MLD) is the most frequent LSD. MLD was
diagnosed in 24% of lipidoses and the calculated birth prevalence was 1.42
per 100,000 for all types combined. Krabbe disease, diagnosed in 17% of ca
ses, also belongs to the more frequent lipid storage diseases in The Nether
lands with a birth prevalence of 1.35 per 100,000. The birth prevalence of
Gaucher disease, commonly regarded as the most frequent lipid storage disea
se is 1.16 per 100,000 for all types combined. The combined birth prevalenc
e for all lipid storage diseases is 6.2 per 100,000 live births. Within the
group of mucopolysaccharidoses (MPSs), MPS I has the highest calculated bi
rth prevalence of 1.19 per 100,000 (25% of all cases of MPS diagnosed), whi
ch is slightly more frequent than MPS IIIA with an estimated birth prevalen
ce of 1.16 per 100,000. As a group, MPS III comprises 47% of all MPS cases
diagnosed and the combined birth prevalence is 1.89 per 100,000 live births
. The birth prevalence of MPS II is 0.67 per 100,000 (1.30 per 100,000 male
live births). All other MPSs are rare. The combined birth prevalence for a
ll MPSs is 4.5 per 100,000 live births. Mucolipidoses and oligosaccharidose
s are very rare with birth prevalences between 0.04 and 0.20 for individual
diseases. Only 49 cases were diagnosed between 1970 and 1996. Their combin
ed birth prevalence is 1.0 per 100,000 live births.