With CRISPR gene editing, unique treatments begin to take off for rare diseases

Paddy Doherty remembers his father as a proud, hard-working family man who stayed physically fit for most of his life. A career in construction and various home improvement projects kept him active until his 60s, when Doherty first caught glimpses of a worrying decline in his dad’s health.

“I noticed him getting breathless on walks. He’d stop for a while and maybe make an excuse for stopping, saying, ‘Oh, isn’t that a lovely tree’ or whatever,” said Doherty, who lives in Ireland. Doctors chalked it up to angina, or chest pain caused by reduced blood flow to the heart, symptomatic of an underlying heart problem.

But two years later, when Doherty’s father died of a sudden heart attack, the true cause was discovered: a rare disease called transthyretin (ATTR) amyloidosis, characterized by a misfolded protein that builds up in the heart and interferes with normal function.

“Patients left untreated with this type of amyloidosis develop heart failure, low blood pressure, horrible bowel disturbance, and eventually become incontinent of urine and feces,” said Julian Gillmore, nephrologist and head of the...