Body Composition and Hormonal Status in Ataxia Telangiectasia

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:

• 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.
• Due to the progressive cerebellar ataxia most of the patients are bound to wheelchair so that their muscle mass is decreased
• Impaired muscle strength is related to apraxia, dystonia, contractures and dyskinesia.
• Low levels of growth hormones (GH). Extracerebellar MRI - lesions in A-T go along with deficiency of the GH axis thus causing nanism.
• Delayed puberty and physical development suggest an abnormal metabolism in muscle cells
• 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

Inclusion criteria

• aim group: clinically and/or genetically diagnosed A-T
• control group: age and sex matched healthy subjects
• age 2-45 years
• written informed consent

Exclusion criteria

• age < 2 or > 45 years
• other diseases with influence on the immunosystem (i.e. diabetes mellitus, malignoma, dialysis-dependent renal failure)
• current medication with hormones