Cloudy with a Chance of Cataracts

What we do know: cataracts are extremely common; they can be present at birth in genetically predisposed individuals or develop later in life – the result of damage accumulated over time. What we do not know with any certainty: how and why they form. Until recently, the consensus was that defective or damaged crystallin proteins in the eye reacted with one another to form light-scattering aggregates – with α-crystallin proteins working against the process. However, while studying strains of mice with point mutations in α-, β-, or γ-crystallin proteins, a team at the Technical University of Munich has shown that this may not be the case. First, the investigation found that mutant proteins were unstable in vitro and appeared at lower levels in the lens than expected. What’s more, the healthy proteins in each mutant appeared to be the source of aggregates, leading the researchers to hypothesize that the ratio of crystallin proteins may be the key to cataract formation. Confirmation, perhaps, that balance is everything.