A case report of recessive myotonia congenita and early onset cognitive impairment: Is it a causal or casual link?

Simona Portaro, Alberto Cacciola, Antonino Naro, Demetrio Milardi, Rosa Morabito, Francesco Corallo, Silvia Marino, Alessia Bramanti, Emanuela Mazzon, Rocco Salvatore Calabrò

Research output: Contribution to journalArticlepeer-review


RATIONALE: Myotonia congenita (MC) is a non-dystrophic myotonia inherited either in dominant (Thomsen) or recessive (Becker) form. MC is due to an abnormal functioning of skeletal muscle voltage-gated chloride channel (CLCN1), but the genotype/phenotype correlation remains unclear.

PATIENT CONCERNS: A 48-year-old man, from consanguineous parents, presented with a fixed muscle weakness, muscle atrophy, and a cognitive impairment. Notably, his brother presented the same mutation but with a different phenotype, mainly involving cognitive function.

INTERVENTIONS: The patient was submitted to cognitive assessment, needle electromyography, brain and muscle MRI, and genetic analysis.

OUTCOMES: The Milan Overall Dementia Assessment showed short-term memory, verbal fluency and verbal intelligence impairment. His genetic analysis showed a recessive splice-site mutation in the CLCN1 gene (IVS19+2T>A). Muscle MRI revealed a symmetric and bilateral fat infiltration of the tensor of fascia lata, gluteus medius, and gluteus maximus muscles, associated to mild atrophy.

DIAGNOSIS: Recessive myotonia congenita was diagnosed.

LESSONS: Further studies should establish if and to which extent the CLCN1 mutation is responsible for this c MC phenotype, taking into account a gene-gene and /or a gene-environment.

Original languageEnglish
Article numbere10785
Pages (from-to)1-7
Number of pages7
Issue number22
Publication statusPublished - Jun 2018


  • Brain/diagnostic imaging
  • Chloride Channels/genetics
  • Cognitive Dysfunction/diagnosis
  • Electromyography/methods
  • Genetic Testing/methods
  • Humans
  • Magnetic Resonance Imaging/methods
  • Male
  • Middle Aged
  • Muscle Weakness/diagnosis
  • Muscle, Skeletal/diagnostic imaging
  • Muscular Atrophy/diagnosis
  • Mutation
  • Myotonia Congenita/complications
  • Phenotype


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