Michael and Matthew Clark are often compared to characters in "The Curious Case of Benjamin Button" flick, due to a regenerative condition that is bringing them back to an infant's mental state.
Michael is 49 years old, and used to serve in Britain’s Royal Air Force, while 39-year-old Matthew worked at Walkers Crisps. They had families of their own, but are now living with their parents in Lincoln, near Lincolnshire, in England.
As Brad Pitt's character did in the popular movie, the brothers are aging backwards. They currently have the mental capacities of seven-year-old boys.
They have been diagnosed with terminal leukodystrophy, a condition which only affects about 100 people in Britain, International Business Times writes.
They are the only brothers suffering from the disease, and their parents have been told that they were the carriers. In an astounding coincidence, both mother Christine and her husband Clark were affected by the rare genetic disorder, and were unaware of it.
"Nobody knows exactly, but it is a genetic condition. Chris and I have been told it is likely we have the same gene deficiency and that there is a 1 in 3 billion chance of two people with the same gene deficiency meeting and becoming parents.
"And our both having this deficiency has caused this to happen to our sons. There is no cure, and they don’t know how to treat it. We still can’t quite believe it. You just imagine there is some sort of cure out there for every disease," Christine explains.
The condition leaves the Clarks' parents powerless, as their "children" throw tantrums while they play board games around the house. Screaming episodes occur as Michael sporadically bounces back to a state of awareness, for a brief moment.
"It is like an adult having a toddler's tantrum. It's obviously worse for him, but it is terrible for us too. There's nothing we can do to help, and we feel absolutely powerless," father Chris says.
Their biggest fear is that, without any known cure for the disease, they will outlive their sons.
"It's very difficult to do anything once progression has occurred. [...] The likelihood that they're on a terminal course are fairly certain, but who knows?," he adds, hopeful.