N. Georgiou et al., Differential clinical and motor control function in a pair of monozygotic twins with Huntington's disease, MOVEMENT D, 14(2), 1999, pp. 320-325
We report a pair of monozygotic Huntington's disease (HD) twins who, althou
gh sharing identical CAG repeat lengths, not only present with marked diffe
rences in clinical symptoms but also behavioral abilities as measured by ou
r experimental procedures. Both HD twins and two healthy control subjects w
ere tested twice over 2 years. Patient A was generally more impaired at a m
otor level, whereas Patient B showed greater attentional impairment; Patien
t B, however, showed more progressive deterioration. The control subjects'
performance remained consistent over the 2-year interval. Patient A clinica
lly had the more hyperkinetic hypotonic variant of the disease, whereas Pat
ient B, who was the more impaired, presented with a more hypokinetic hypert
onic (rigid) variant. The influences of epigenetic pre- and postnatal envir
onmental factors should not be ignored.