Body mass index is inversely correlated with the expanded CAG repeat length in SCA3/MJD patients

Cerebellum. 2012 Sep;11(3):771-4. doi: 10.1007/s12311-011-0326-6.

Abstract

Spinocerebellar ataxia type 3, also known as Machado-Joseph disease (SCA3/MJD), is an autosomal dominant neurodegenerative disorder with no current treatment. We aimed to evaluate the body mass index (BMI) of patients with SCA3/MJD and to assess the correlations with clinical, molecular, biochemical, and neuroimaging findings. A case-control study with 46 SCA3/MJD patients and 42 healthy, non-related control individuals with similar age and sex was performed. Clinical evaluation was done with the ataxia scales SARA and NESSCA. Serum insulin, insulin-like growth factor 1 (IGF-1) and magnetic resonance imaging normalized volumetries of cerebellum and brain stem were also assessed. BMI was lower in SCA3/MJD patients when compared to controls (p = 0.01). BMI was associated with NESSCA, expanded CAG repeat number (CAG)n, age of onset, age, disease duration, and serum insulin levels; however, in the linear regression model, (CAG)n was the only variable independently associated with BMI, in an inverse manner (R = -0.396, p = 0.015). In this report, we present evidence that low BMI is not only present in SCA3/MJD, but is also directly related to the length of the expanded CAG repeats, which is the causative mutation of the disease. This association points that weight loss might be a primary disturbance of SCA3/MJD, although further detailed analyses are necessary for a better understanding of the nutritional deficit and its role in the pathophysiology of SCA3/MJD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Body Mass Index*
  • Case-Control Studies
  • Cerebellum / pathology
  • DNA Repeat Expansion / genetics*
  • Deglutition Disorders / etiology
  • Disease Progression
  • Female
  • Humans
  • Insulin / blood
  • Insulin-Like Growth Factor I / metabolism
  • Machado-Joseph Disease / genetics*
  • Machado-Joseph Disease / pathology*
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Neurologic Examination
  • Nutritional Status
  • Weight Loss / physiology

Substances

  • Insulin
  • Insulin-Like Growth Factor I