Don't be fooled, White and White
patterned Aussies are not rare nor worth a lot of money. The majority of
these are from merle to merle breedings that have serious genetic
defects that make them require special training and handling. Although not
all are from the double merle gene, a Merle to Solid or Tri can product mis-marked
white patterned Aussies too. The Double Merle gene is different than Irish
Pattern which is the amount of white patterning a dog will have.

Recommended site
for more information:
http://www.lethalwhites.com/
http://www.ashgi.org/articles/fact_white.htm
http://www.ashgi.org/articles/color_white_fright.htm
http://www.aussielads.com/LethalWhite%20INFO.htm
http://collectinaussies.com/Lethals.html