title: Body mass index is inversely correlated with the expanded CAG repeat length in SCA3/MJD patients.
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.
authors.affiliation: Postgraduate Program in Medical Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Jonas Alex Morales
authors.initials: JA
authors.lastname: Saute
authors.forename: Andrew Chaves Feitosa da
authors.initials: AC
authors.lastname: Silva
authors.forename: Gabriele Nunes
authors.initials: GN
authors.lastname: Souza
authors.forename: Aline Dutra
authors.initials: AD
authors.lastname: Russo
authors.forename: Karina Carvalho
authors.initials: KC
authors.lastname: Donis
authors.forename: Leonardo
authors.initials: L
authors.lastname: Vedolin
authors.forename: Maria Luiza
authors.initials: ML
authors.lastname: Saraiva-Pereira
authors.forename: Luis Valmor Cruz
authors.initials: LV
authors.lastname: Portela
authors.forename: Laura Bannach
authors.initials: LB
authors.lastname: Jardim
mesh_terms: D000328:Adult; D015992:Body Mass Index; D016022:Case-Control Studies; D002531:Cerebellum / Q000473:pathology; D042622:DNA Repeat Expansion / Q000235:genetics*; D003680:Deglutition Disorders / Q000209:etiology; D018450:Disease Progression; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D017827:Machado-Joseph Disease / Q000235:genetics* / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D009752:Nutritional Status; D015431:Weight Loss / Q000502:physiology
chemical_list: D007328:Insulin; D007334:Insulin-Like Growth Factor I
references.citation: Mov Disord. 2011 Mar;26(4):731-5
references.pmid: 21506152
references.citation: Neurology. 2009 Aug 4;73(5):385-92
references.pmid: 19652143
references.citation: Neurology. 2006 Jun 13;66(11):1717-20
references.pmid: 16769946
references.citation: Genetika. 2005 Jun;41(6):830-7
references.pmid: 16080609
references.citation: Brain. 1998 Apr;121 ( Pt 4):589-600
references.pmid: 9577387
references.citation: Neurobiol Dis. 2002 Dec;11(3):410-24
references.pmid: 12586550
references.citation: Neurology. 2008 Nov 4;71(19):1506-13
references.pmid: 18981372
references.citation: Eur J Neurol. 2008 Apr;15(4):371-6
references.pmid: 18312406
references.citation: Neurology. 2007 Aug 28;69(9):917-24
references.pmid: 17724296
references.citation: Hum Mol Genet. 2009 Nov 15;18(22):4282-95
references.pmid: 19666958
references.citation: Lancet Neurol. 2010 Sep;9(9):885-94
references.pmid: 20723845