A study to determine the early features of late-onset Pompe disease (acid maltase deficiency) is seeking 250 adults who have a clinical diagnosis of unclassified limb-girdle muscular dystrophy (LGMD), an uncertain diagnosis of other forms of muscular dystrophy (MD),or an unclassified myopathy(muscle disease)who do not carry any biochemical, metabolic, enzymatic, serologic (blood), molecular or pathologic diagnostic marker that confirms their diagnosis.
Investigators at New York University hope to identify individuals with late-onset Pompe disease who may then qualify to begin enzyme replacement therapy.
Such a study is needed, the investigators say, because the average time between symptom onset and diagnosis of late-onset Pompe disease is eight to 10 years, reflecting a great deal of diagnostic ambiguity associated with this disorder.
They say several factors play a role in the long diagnostic delay, including the slow progression of late-onset Pompe disease during the early phase; a lack of awareness of late-onset Pompe disease in the medical community; the lack of specificity of the initial symptoms, which are generally weakness of the limb girdles (muscles around the hips and shoulders); and the nonuniform distribution of glycogen deposits in the muscles, so that a small muscle biopsy sample may not show these tell-tale signs of Pompe disease.
Prospective participants must be at least 18 years old and have an unconfirmed or unclassified diagnosis of LGMD, myotonic dystrophy, Emery-Dreifuss MD, oculopharyngeal MD, distal MD, facioscapulohumeral MD, polymyositis, hyperthyroid myopathy, hypothyroid myopathy, mitochondrial myopathy, or another unclassified myopathy. They also must meet other study criteria.
The investigators will discuss the study over the phone with each prospective participant, after which, with the participant's consent, they will request a blood sample for analysis of alpha-glucosidase (acid maltase), the enzyme that is deficient in Pompe disease.
The participant will receive a kit and instructions from the study investigators to expedite the blood draw and shipping. The blood sample can be drawn at a location of the participant's choice. No travel to New York is necessary. The study is funded by Genzyme Corp., which has developed enzyme replacement therapies for Pompe disease.
In addition, the investigators will require participants to fill out a questionnaire documenting the course of their illness. Copies of medical records, including office notes and any available test results, also will be requested.
For more information, contact Edward Nunziato, research assistant in the Division of Neurogenetics at New York University School of Medicine at firstname.lastname@example.org (preferred) or (212)263-5912.
Editor's note 7/15/11: This study closed to enrollment of new participants July 15, 2011.