Body composition, muscle strength and hormonal status in patients with ataxia telangiectasia: a cohort study

Background: Ataxia-telangiectasia (A-T) is a devastating human autosomal recessive disorder that causes progressive cerebellar ataxia, immunodeficiency, premature aging, chromosomal instability and increased cancer risk. Affected patients show growth failure, poor weight gain, low body mass index (BMI), myopenia and increased fatigue during adolescence. The prevalence of alterations in body composition, muscle strength and hormonal status has not been well described in classical A-T patients. Additionally, no current guidelines are available for the assessment and management of these changes. Methods: We analyzed body composition, manual muscle strength and hormonal status in 25 A-T patients and 26 age-matched, healthy controls. Bioelectrical impedance analysis (BIA) was performed to evaluate the body composition, fat-free mass (FFM), body cell mass (BCM), extracellular matrix (ECM), phase angle (PhA), fat mass (FM) and ECM to BCM ratio. Manual muscle strength was measured using a hydraulic hand dynamometer. Results: The BMI, FFM and PhA were significantly lower in A-T patients than in controls (BMI 16.56 +/- 3.52 kg/m(2) vs. 19.86 +/- 3.54 kg/m(2); Z-Score: -1.24 +/- 1.29 vs. 0.05 +/- 0.92, p < 0.001; FFM 25.4 +/- 10.03 kg vs. 41.77 +/- 18.25 kg, p < 0.001; PhA: 4.6 +/- 0.58 degrees vs. 6.15 +/- 0.88 degrees, p < 0.001). Manual muscle strength was significantly impaired in A-T patients compared with controls (10.65 +/- 10.97 kg vs. 26.8 +/- 30.39 kg, p < 0.0001). In addition, cortisol and dehydroepiandrosterone sulfate (DHEAS) levels were significantly lower in A-T patients than in controls. Conclusion: Altered body composition, characterized by depleted BMI, PhA and BCM; by the need to sit in a wheelchair; by altered hormone levels; and by poor muscle strength, is a major factor underlying disease progression and increased fatigue in A-T patients.