title: Choline Kinase Beta-Related Muscular Dystrophy, Appearance of Muscle Involvement on Magnetic Resonance Imaging.
abstract: BACKGROUND
  Clinical presentation with motor delay, proximal weakness, and learning difficulties raise the possibility of a dystrophinopathy, dystroglycanopathy, or myotonic dystrophy. This differential should also include the more recently described choline kinase beta-related muscular dystrophy. This condition is typically characterized by large and abnormally distributed mitochondria on muscle biopsy, which can distinguish this condition from the other muscle conditions in the differential.
  
  
  METHODS
  We present a boy with choline kinase beta mutations with relatively mild clinical manifestations, including proximal weakness, learning difficulties and elevated creatine kinase. Investigations included muscle magnetic resonance imaging (MRI) with T1 axial sequences through thigh and calves, and needle muscle biopsy of the left vastus lateralis muscle.
  
  
  RESULTS
  MRI showed involvement mainly of the quadriceps femoris, sartorius, and adductor magnus, with selective sparing of the gracilis, hamstrings, and adductor longus and brevis. Muscle biopsy revealed chronic dystrophic features. Oxidative stains demonstrated enlarged mitochondria accentuated peripherally or present diffusely in a few fibres giving a coarsely stippled appearance. A homozygous C.722A>G (p.Asn241Ser) mutation was detected in exon 6 of the CHKB gene.
  
  
  CONCLUSIONS
  This selective pattern of skeletal muscle involvement might be helpful for identifying other patients with this condition, even in the absence of diagnostic muscle pathology.
authors.affiliation: Department of Paediatric Neurology, Royal Preston Hospital, Preston, United Kingdom. Electronic address: Christian.degoede@lthtr.nhs.uk.
authors.forename: Christian
authors.initials: C
authors.lastname: De Goede
authors.affiliation: Department of Radiology, Royal Preston Hospital, Preston, United Kingdom.
authors.forename: Teik
authors.initials: T
authors.lastname: Oh
authors.affiliation: Department of Neuropathology, Royal Preston Hospital, Preston, United Kingdom.
authors.forename: Jacob
authors.initials: J
authors.lastname: Joseph
authors.affiliation: Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital, London, United Kingdom.
authors.forename: Francesco
authors.initials: F
authors.lastname: Muntoni
authors.affiliation: Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital, London, United Kingdom.
authors.forename: Caroline
authors.initials: C
authors.lastname: Sewry
authors.affiliation: Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital, London, United Kingdom.
authors.forename: Rahul
authors.initials: R
authors.lastname: Phadke
mesh_terms: D002648:Child; D002797:Choline Kinase / Q000235:genetics*; D003937:Diagnosis, Differential; D006801:Humans; D007866:Leg / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D018482:Muscle, Skeletal / Q000473:pathology*; D009136:Muscular Dystrophies / Q000175:diagnosis / Q000201:enzymology / Q000235:genetics* / Q000473:pathology*
chemical_list: C542592:CHKB protein, human; D002797:Choline Kinase
keywords: choline kinase beta; learning difficulties; mitochondria; muscle MRI; muscular dystrophy