This is a 24-month, observational study of up to 1000 participants with Limb Girdle Muscular Dystrophy (LGMD), Myotonic Dystrophy Type 2 (DM2), and late onset Pompe disease (LOPD).

Limb Girdle Muscular Dystrophy (LGMD) comprise a group of disorders made up of over 30 mutations which share a common phenotype of progressive weakness of the shoulder and hip girdle muscles. While the individual genetic mutations are rare, as a cohort, LGMDs are one of the four most common muscular dystrophies.

Myotonic Dystrophy Type 2 (DM2) is a more recently discovered, rare type of myotonic dystrophy. DM2 is inherited in an autosomal dominant pattern and is caused by an unstable CCTG expansion. DM2 affects the muscles and other body systems (e.g. heart and eyes).

Pompe disease is a rare, multisystemic, hereditary disease which is caused by pathogenic variations in the GAA gene. Late onset Pompe disease (LOPD) refers to cases in which hypertrophic cardiomyopathy did not manifest or was not diagnosed at or under the age of 1 year. LOPD is characterized by skeletal muscle weakness which causes mobility problems and impacts the respiratory system.

The overall goal of this project is to extend prior observational studies conducted within the GRASP LGMD network to define the key phenotypes as measured by standard clinical outcome assessments (COAs) for multiple rare types of muscular dystrophy to hasten therapeutic development.

Inclusion Criteria:

1. Age between 6-50 years at enrollment
2. Clinically affected (defined as weakness on bedside evaluation in a pattern consistent with proximal weakness)
3. Genetic confirmation of a LGMD, DM2, or LOPD
4. FVC above 30% of predicted

Exclusion Criteria:

1. Any other illness that would interfere with the ability to undergo safe testing or would interfere with interpretation of the results in the opinion of the site investigator
2. Participation in a clinical trial receiving an investigational product

The study seeks to enroll ambulatory individuals aged 6-50 years at enrollment who are clinically affected by LGMD, DM2, or LOPD.

Aggregated and deidentified data will be shared with qualified investigators upon majority approval of the LGMD investigators.