A Multicenter Phenotype-Genotype Analysis of LGMD Patients in China

This is multicentered-based, prospective, and observational study, which mainly focuses on the diagnosis and progression of limb-girdle muscular dystrophies (LGMD) in China. the investigators collect patient data including basic information, strength evaluations, genetic data, electromyography results, pathology imaging from muscle biopsies, and MRIs. Previously collected patient data may also be enrolled in this study.

• Electromyography (Diagnostic test): Electromyography (EMG) would be used at the baseline for dignoisis and furtue analysis.
• IDEAL MRI (Diagnostic test): Muscle-speciifc sequences (e.g. IDEAL) would be used to scan patients at baseline and follow-up stages to characterize the fat fraction and atrophy in different muscles.

Primary outcomes

• Changes in NSAA score [Baseline, Year 1, Year 3, Year 5]: The North Star Ambulatory Assessment (NSAA) is a 17-item rating scale with a score range of 0-34. It is used to measure the functional motor abilities of ambulant patients with muscular dystrophy. A lower NSAA score indicates more severe damage to the participant's motor capability.

Secondary outcomes

• Changes in muscle fat infiltration [Baseline, Year 3, Year 5]: The muscle-specific fat fraction can be calculated with special MRI sequences such as IDEAL or Dixon in the region of interest. An deep-learning based tool is applied to segment individual muscles.
• Changes in 6 Minute Walk Test [Baseline, Year 3, Year 5]: The 6-Minute Walk Test is a sub-maximal exercise test used to assess aerobic capacity and endurance. The distance covered in 6 minutes serves as the outcome for comparing changes in performance capacity.
• Changes in 10 Metre Walk Test (10MWT) [Baseline, Year 3, Year 5]: The 10 Metre Walk Test is a performance measure used to assess walking speed in meters per second over a short distance. It can be employed to determine functional mobility, gait, and vestibular function

Sex: All, ages: 10 Years to any

Inclusion Criteria:

* Identified with variants regarding LGMD related genes revealed by genetic sequencing
* Progressive weakness involving shoulder girdle and/or pelvic girdle
* Myopathic changes in electromyography or in pathological studies

Exclusion Criteria:

* Identified with variants in other genes (non-LGMD related) that may cause muscular dystrophies

• Chongbo Zhao, PhD, Study director, Huashan Hospital