Study of BBP-418 in Patients With LGMD2I

Inclusion Criteria: * Have a body weight \>30 kg * Have a genetically confirmed diagnosis of LGMD2I and be clinically affected (defined as demonstrating clinical weakness on bedside evaluation in either a limb-girdle pattern, or in a distal extremity) * Able to complete the 10-meter walk test in ≤ 12 seconds unaided ("moderate disease") or are with "severe disease"/non-ambulatory as defined by being unable to complete the 10-meter walk unaided in \>12 seconds * Willing to use an adequate method of contraception from time of consent through 12 weeks after last dose * Previous enrolment in the Natural History study MLB-01-001 Exclusion Criteria: * Evidence of clinically significant concomitant disease, including: * Any history of a gastrointestinal condition, including surgeries, which may affect absorption after oral administration * Any significant concomitant medical condition, including cardiac, pulmonary, renal, hepatic or endocrine disease other than that associated with LGMD2I * Any condition other than LGMD2I requiring therapy with prescription medicine (medication for common and mild concomitant conditions may be permitted after consultation with the PI) * Any other laboratory, vital sign, ECG abnormality, or clinical history or finding that, in the investigator's opinion, is likely to unfavorably alter the risk-benefit of study participation, confound study results, or interfere with study conduct or compliance * If pregnant and/or breastfeeding or planning to conceive children within the projected duration of the study through 12 weeks after the last dose of study treatment. * History of drug abuse including alcoholism within 2 years prior to consenting * Use of ribose or other sugar alcohol-containing supplement within 60 days of Day 1 * Use of a corticosteroid within 60 days of Day 1 * Presence of a platelet disorder, bleeding disorder or other contraindication to muscle biopsy * Actively on an experimental therapy or device or was on an experimental therapy or device within 60 days prior to Day 1.