Peter Špalek
Pompe disease is a rare underdiagnosed inherited autosomal recessive metabolic disorder caused by deficiency of lysosomal
acid alfa-glucosidase (GAA) activity. It is characterised by the accumulation of glycogen in muscle tissue that
leads to progressive myopathy. In general, there is a correlation between the severity of residual enzyme activity and
the severity of clinical phenotype. Infantile form has no residual enzyme activity and is associated with severe muscle
weakness, cardiomyopathy, hepatopathy and death occurs usually within the first year. Juvenile form has an onset in
child age, has some residual GAA activity (3-10%) and a severe progressive myopathy. Adult form is the most frequent,
over 80% patients have the late-onset Pompe disease. Adult form has some residual GAA activity (10-25%). The clinical
hallmark of adult-onset Pompe disease is a progressive myopathy. However, some adult forms present with certain
phenotypic diversity causing difficulties in diagnosing and diagnostic pitfalls. The course of Pompe disease was usually
progressive, disabling and often fatal. There was no treatment for Pompe disease until the end of 20th century. The
recent development in enzymatic replacement therapy (ERT) with recombinant alfa-glucosidase has improved the life
expectancy and quality of life with improvements of muscle motor and muscle respiratory function. The best results
are achieved in patients with Pompe disease diagnosed in early stages. Therefore, early diagnosis of Pompe disease is
of crucial importance. Dried blood spot test provides a rapid and reliable screening method for determination of GGA
deficiency. In 2008 we started a project of active screening for Pompe disease patients in Slovakia using dried blood
spot test. We tested 2654 persons at risk and found in 12 out of them GGA deficiency. In all 12 patients the diagnosis of
Pompe disease was definitively confirmed by measurement of decreased enzyme activity in leukocytes and by DNA verification
of pathogenic mutations in gene for GAA. The patients receive ERT. Late diagnosis in advanced stages of the
disease deprives the benefits of ERT. Therefore, early diagnosis of Pompe disease is of significant importance for the
prognosis of Pompe disease patients. The use of dried blood spots should be a routine procedural component of clinical
practice for all risk persons continually for coming years.