A Diagnostic Dilemma in a Family with Cystinuria Type B Resolved by Muscle Magnetic Resonance

Guja Astrea, Iulia Munteanu, Denise Cassandrini, Suzanne Lillis, Rosanna Trovato, Elena Pegoraro, Giovanni Cioni, Eugenio Mercuri, Francesco Muntoni, Roberta Battini

Research output: Contribution to journalArticlepeer-review


Background Congenital myopathies are inherited primary disorders of the muscle caused by mutations affecting structural, contractile, or regulatory proteins. In the more than 20 genes associated to these conditions, ryanodine receptor type 1 gene (RYR1) is responsible for the most common forms and is associated with a wide range of clinical phenotypes and pathological findings. Magnetic resonance imaging of muscle has been used increasingly to direct genetic testing in myopathies. Patient Description We describe a consanguineous family affected by cystinuria type B, a metabolic condition linked to chromosome 19q13.2, and a different muscle phenotype that, although related to a congenital myopathy, does not have the striking histological features helping in direct genetic tests. Results The assessment of the selective involvement on muscle magnetic resonance imaging allowed the suspicion of RYR1 as the most likely gene responsible for this myopathy. The diagnosis was subsequently confirmed by the finding of a recessive RYR1 mutation. Conclusions The occurrence of congenital myopathy together with cystinuria type B is reported for the first time. The use of muscle magnetic resonance imaging and the homozygosity by descent in SLC7A9, a gene flanking RYR1, allowed us to discover a new mutation in the RYR1 gene.

Original languageEnglish
Pages (from-to)548-551
Number of pages4
JournalPediatric Neurology
Issue number5
Publication statusPublished - May 1 2015


  • congenital myopathy
  • cystinuria type B
  • muscle magnetic resonance
  • RYR1

ASJC Scopus subject areas

  • Clinical Neurology
  • Pediatrics, Perinatology, and Child Health
  • Developmental Neuroscience
  • Neurology
  • Medicine(all)


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