Usher syndrome is the most common form of combined congenital deaf-blindness in humans and affects 1 in 6,000 of the population. It is a recessive inherited disease that is both clinically and genetically heterogeneous. In the most severe cases, patients are born deaf and begin to suffer from a degeneration of the retina in puberty, ultimately resulting in complete blindness. These patients experience major problems in their day-to-day life... 
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