He is deaf and nearly blind, but don't tell him that.
Pink nose, sky blue eyes, and white fur with some patches of liver. He is a large mini Aussie Shepherd or a small standard Aussie.
His condition is genetic ("homozygous merle", "double merle", or, incorrectly, "lethal white") and is entirely avoidable by doing basic research before allowing your dog to get pregnant. Simply don't breed two merle dogs together.
Like most Australian Shepherds, he is extremely active. He is a regular at the local park trails and dog parks.