Background: Lysosomal Storage Diseases (LSD) are rare and multisytemic diseases which are caused by lysosomal enzyme deficiencies leading into accumulation of waste products due to an interruption in the decomposition process. Due to the low prevalence and therefore limited disease awareness as well as the fact that LSD patients present with unspecific symptoms the final diagnosis is often made after a long delay. The aim of this German-wide survey was to characterize the period between onset of symptoms and final diagnosis regarding e.g. self-perceived health, symptom burden and false diagnoses for patients with selected LSDs (Fabry disease (FD), Gaucher disease (GD) and Mucopolysaccharidosis type II (MPS II).
Methods: The study was conducted as a telephone based cross-sectional survey. All patients living in Germany with a confirmed diagnosis of FD, GD or MPS II were eligible to participate. The questionnaire was provided in advance in order to enable the participants to prepare for the interview. Only descriptive analyses were carried out. Single analyses were not carried out for all three patient groups due low case numbers.
Results: Of the overall population, 39 patients have been diagnosed with FD, 19 with GD and 11 with MPS II with the majority of patients being index patients. The majority of FD patients reported their current health status as "satisfactory" or better (79.5%). Self-perceived health status was observed to be at least stable or improving for the majority of FD patients compared to the year prior to diagnosis. The most frequently reported symptoms for patients with FD were paraesthesias (51.3%), whereas patients with GD reported a tendency for bleeding, blue spots or coagulation disorder (63.2%) as well as hepatomegaly and/or splenomegaly (63.2%) as the most commonly appearing symptoms. The number of patients reporting misdiagnoses was n = 5 (13.5%) for patients with FD and n = 5 (27.8%) for patients with GD. The median duration of the diagnostic delay was 21.0 years for FD, 20.0 years for GD and 2.0 years for MPS II.
Conclusions: This study showed that self-perceived status of health for patients might improve once the final correct diagnoses has been made and specific treatment was available. Furthermore, it was observed that diagnostic delay is still high in Germany for a relevant proportion of affected patients. Further challenges in the future will still be to increase awareness for these diseases across the entire healthcare sector to minimize the diagnostic delay.