Body Composition, Muscle Strength and Hormonal Status in Patients With Ataxia Telangiectasia Compared to Healthy Controls

Ataxia telangiectasia (A-T) is a devastating human recessive disorder characterized by progressive cerebellar ataxia, immunodeficiency, chromosomal instability, and cancer susceptibility. In addition to that, a high percentage of patients show dystrophy, growth retardation and poor weight gain. There are only a few studies assessing this problem and the exact variations concerning body composition, muscle strength and hormonal status are widely unknown.

Major factors may be responsible for altered body composition:

1. Immunodeficiency and chronic disease are important influences on growth and physical development. The constantly catabolic situation of A-T patients has a major impact on dystrophy.
2. Due to the progressive cerebellar ataxia most of the patients are bound to wheelchair so that their muscle mass is decreased
3. Impaired muscle strength is related to apraxia, dystonia, contractures and dyskinesia.
4. Low levels of growth hormones (GH). Extracerebellar MRI - lesions in A-T go along with deficiency of the GH axis thus causing nanism.
5. Delayed puberty and physical development suggest an abnormal metabolism in muscle cells
6. There are autopsy reports informing about reduced mass of the adrenal cortex that may be reflected in a lower hormone release of steroid hormones.

The aim of the proposal is to explore the exact body composition, the manual muscle strength, the hormonal status in patients with A-T compared to healthy subjects matched for sex and age. One study visit is performed in all A-T patients and healthy subjects:

• To evaluate weight and length of all subjects
• To analyze the exact structure of single body compartments such as the lean mass, the water compartment or the fat compartment using bioelectrical impedance analysis
• To determine the subcutaneous fat fold thickness using calipometry
• To investigate the nourishment habits and diet detected by nutritional diary
• To analyze the manual muscle strength with a hand dynamometer
• To determine the physical development in the A-T cohort by Tanner scores
• To evaluate stage of sexual development and puberty in female A-T patients by ultrasonic of the inner genitalia
• To get a detailed hormonal status including thyroid-stimulating hormone (TSH), luteinizing hormone (LH), follicle stimulating hormone (FSH), GH, cortisol, DHEAS, estradiol, testosterone, progesterone, insulin like growth factor-binding protein 3 (IGF-BP3), etc in serum blood