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

K.D. Mathews, MD C.M. Stephan, BSN, MA K. Laubenthal, PT, MS, PCS T.L. Winder, PhD D.E. Michele, PhD S.A. Moore, MD, PhD K.P. Campbell, PhD MYOGLOBINURIA AND MUSCLE PAIN ARE COMMON IN PATIENTS WITH LIMB-GIRDLE MUSCULAR DYSTROPHY 2I Fukutin-related protein (FKRP; OMIM #606596) is critical for the appropriate glycosylation of -dystroglycan, a component of the dystrophinglycoprotein 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.