Congenital Multiminicore Myopathy
Multiminicore disease (MmD) is a hereditary congenital myopathy characterized by multiple cores on muscle biopsy. Marked clinical variability corresponds to genetic heterogeneity: the most frequent phenotype is characterized by spinal rigidity and early scoliosis, and respiratory impairment is due to recessive mutations in the SEPN1 gene encoding selenoprotein-1, whereas recessive mutations in the skeletal muscle ryanodine receptor (RYR1) gene have been associated with a wider range of clinical features comprising external ophthalmoplegia, distal weakness, and wasting or predominant hip girdle involvement resembling central core disease (CCD). The pathogenetic mechanisms of RYR1-related MmD are currently not well understood but are likely to involve altered excitability and/or changes in calcium homeostasis. The presence of calcium-binding motifs within the selenoprotein also suggests a possible role in calcium handling. Muscle MRI may aid genetic testing as distinct patterns of selective muscle involvement can be detected depending on the genetic background.
KeywordsMinicore Hip luxation Skeletal deformities Myopathy Muscle
- 1.Engel AG, Gomez MR, Groover RV. Multicore disease: a recognised congenital myopathy associated with multifocal degeneration of muscle fibres. Mayo Clin Proc. 1971;46:661–81.Google Scholar