Myoglobinuria and muscle pain are common in patients with limb-girdle muscular dystrophy 2I

Abstract

Fukutin-related protein ( FKRP; OMIM #606596) is critical for the appropriate glycosylation of α-dystroglycan, a component of the dystrophin-glycoprotein complex. The 12-kb FKRP gene is composed of 3 noncoding exons and 1 exon encompassing the entire open reading frame.1 Mutations in FKRP cause autosomal recessive muscular dystrophy with a wide range of clinical severity. A common missense mutation, c.826C>A (p.L276I), has been identified. Generally, individuals homozygous for this mutation have a mild form of limb-girdle muscular dystrophy (LGMD) 2I, compound heterozygotes with 1 c.826C>A allele have a more severe form of LGMD 2I, and those with 2 unique alleles are most severely affected, including some with congenital muscular dystrophy.1,2 We report a high incidence of myoglobinuria and muscle pain in a retrospective study of patients with LGMD 2I. ### Methods. #### Standard protocol approvals, registrations, and patient consents. Institutional Review Board approval was obtained for all recruitment and data collection. Written informed consent was obtained from all participants or their legal guardians. This study was posted on clinicaltrials.gov (NCT00313677). All patients with FKRP mutations were eligible for enrollment from 2006 to the present. #### Genetic testing. FKRP mutations were confirmed in the University of Iowa …