IPA/ Erasmus MC Pompe Survey

Pompe disease is an inherited lysosomal storage disorder caused by the
deficiency of acid alpha-glucosidase. The disease is characterized by lysosomal
accumulation of glycogen in virtually all body tissues but most marked in
heart, skeletal muscle, and liver. Pompe disease has an incidence of
approximately 1 in 40,000 births. Essentially there is a broad spectrum of
disease ranging from a rapidly progressive form (classic infantile Pompe
disease) to a more slowly progressive form (late-onset Pompe disease) with
considerable variability and overlap existing between these extremes.

Patients with classic infantile Pompe disease, typically present with symptoms
within the first months of life, with cardiomyopathy and generalized muscle
weakness. Most patients die from cardiac and/or respiratory failure before they
reach 1 year of age.The late-onset form of Pompe disease progresses less
rapidly. Symptoms may appear during childhood or as late as the seventh decade
of life. Patients may present with a progressive proximal myopathy and variable
respiratory involvement. Eventually, most patients become wheelchair-bound,
require ventilator support and ultimately succumb to respiratory failure.

Since 2006 Myozyme® (alglucosidase alfa), a recombinant human acid
alpha-glucosidase has received marketing approval use as enzyme replacement
therapy (ERT) for the treatment of Pompe disease.
In 2002 the study *Investigation into the clinical condition of late onset
Pompe patients*, also known as the *IPA/ Erasmus MC Pompe Survey*, started. In
2009 the present protocol was introduced to update the IPA/ Erasmus MC Pompe
Survey to the new situation, in which an approved therapy for Pompe disease has
become available. The survey is a joint initiative of Erasmus MC and the
International Pompe Association, a worldwide federation of Pompe disease
patient groups.

The aim of the Survey is to better understand the variability and progression
of Pompe disease and to continue to monitor and evaluate the long-term effects
of available treatment options and support measures including ERT with
alglucosidase alpha and any other approved therapy in the future.

The IPA/ Erasmus MC Pompe Survey is an international, observational program for
patients with Pompe disease; no experimental intervention is involved. The
patients will complete standardized questionnaires on their clinical condition,
the impact of the disease on daily life activities and quality of life.

The extent of burden will only be, completing the questionnaires and this will
be about 1.5 hours every year.