Siblings with only known case of genetic flaw in the world find DNA hope in US

A brother and sister born with a genetic condition so rare there are no other confirmed cases in the world have found a partial DNA match in America.

Five-year-old Lily Arnott and her brother Benjamin, 3, from Penicuik, were both born with an extra chromosome, made up of uneven parts of chromosomes 21 and 16.

They are thought to be the only people in the world with a chromosome disorder so unique that there is no name for it.

As a result of the chromosome imbalance, Lily and Benjamin have global development delay, learning disabilities and hypermobility with their condition most similar to Down’s syndrome.

Three-year-old Benjamin has a chromosome disorder so rare the only other recorded case is his big sister Lily, five.

Both are still in nappies, struggle with verbal communication and have a variety of health complications. Lily is prone to renal infections and Benjamin has a similar challenge with chest infections.

Now a glimmer of hope has been offered to parents Kenny, 42, and Crystal Arnott, 38, after they signed up to an international database that helps track down and pair families with extremely rare chromosome and gene disorders.

The Arnotts are among 684 families in Scotland who have signed up to the database, run by Surrey-based charity, Unique.

While a complete match has not been found, the family has been paired with four people in America that have similar chromosome disorders.

The Arnott family have found a partial genetic match in the USA.

Among these is a 27-year-old man from the USA who the Arnotts hope will help them begin to piece together the puzzle of Lily and Benjamin’s development.

Mr Arnott said: “As our children are the only people in the world on record with this genetic makeup we have no way to gauge their development.

“Speaking to families who have similar children, maybe older, could help us work out what road they may go down.

“Ordinary milestones mean nothing to us, but this will hopefully give us part of the puzzle and help give us more of an idea of where our children should be.”

Mr Arnott said his five-year-old Lily loves playing dress up and dancing but can't attend dance classes because of her health conditions.

“It can be lonely”

Mr Arnott praised their local primary school and support services for the “excellent support” provided but said "it can be lonely” being the only family in the world living with this rare genetic condition.

“We’ve had dark days,” he said.

The father added: “It was really difficult when it was first confirmed.The genetic counsellors were great but they couldn't tell us what the long-term outcome would be for Lily and Benjamin. Every day we are learning as we go.”