Body composition in patients with Huntington's disease

Huntington*s disease (HD) is a severe neurodegenerative disorder with an
autosomal dominant mode of inheritance. Characteristic features of the disease
are unwanted choreatic movements, cognitive decline and behavioural
disturbances. Another common feature of HD is unintended weight loss, the cause
of which is not yet elucidated. Pilot studies measuring body composition in HD
patients have suggested loss of adipose tissue stores in HD. However, these
reports did not investigate the change in body composition at different stages
of the disease, or did not incorporate data on healthy subjects for comparison.
The aim of the present study aim is to evaluate body composition in patients
with HD at different stages of the disease in comparison to healthy controls in
order to assess whether these patients have lower fat mass, lean body mass or
both. Moreover, as CAG repeat expansion size was recently shown to be
associated with weight loss, we will assess whether CAG repeat expansion size
is also related to body composition. Body composition will be assessed using
bioelectrical impedance analysis. The expectations are that HD patients will
have lower fat mass compared with matched healthy control subjects, and that
this difference will be greater for men than for women. Furthermore, patients
in a more advanced stage of the disease will have lower fat mass than patients
in a less advanced stage of the disease, and a higher CAG repeat length will
correlate with lower fat mass.

The aim of the study is to answer the following questions:

1: Is there a difference in body composition between patients with HD and
matched controls?
2: Does HD affect body composition differently in men and women?
3: Are changes in body composition in HD patients associated with disease stage?
4: Is CAG repeat length associated with fat- and lean muscle mass?

Observational study

The burden and risks for participants are negligible. The measurements will
only be performed once and the total session will take less than 40 minutes.
Bioelectrical Impedance Analysis (BIA) is a harmless and non-invasive method.
Subjects are requested to lie down in bed, than four electrodes are attached to
hands and feet. The BIA than sends a very weak electrical signal through the
body. Subsequently, from the electrical resistance which the signal encounters,
the fat percentage can be deduced. The BIA measurement only lasts a few seconds
and the subject will not sense the signal in any respect.