Study: Disease Severity, Older Age and Point Mutation Raise Risk of Diabetes in FA

Among people with Friedrich’s ataxia (FA), being older, having a more severe condition, and a point mutation raise the risk for developing diabetes, according to a recent study.

The study, “Prevalence, Risk, and Management of Diabetes in Friedreich’s Ataxia,” was presented at the 80th Scientific Sessions, held virtually and sponsored by the American Diabetes Association.

FA is commonly caused by a repeated segment of DNA in both copies of the FXN gene, which provides instructions for making the frataxin protein. Specifically, people with FA have an expansion of a GAA repeat, a sequence of three nucleotides (the building blocks of DNA) where G stands for guanine and A for adenine. Less commonly, however, FA patients may have a GAA  in one copy of FXN and a point mutation, or a change in a single nucleotide, in the other.

Up to 20% of FA patients develop diabetes. The risk factors for diabetes and how best to manage the condition in FA, however, remain unclear.

To address this knowledge gap an international team from the U.S. and Switzerland used medical records from the large multi-site and longitudinal FA Outcomes Measures Study (FACOMS, NCT03090789). The observational study continues to recruit participants at locations in the U.S., Australia, New Zealand, and Canada. More information is available here.

In a group of 1,020 patients, the researchers evaluated the presence of point mutations and diabetes. The modified FA Rating Scale (mFARS) of neurological symptoms was used to assess disease severity. In the subgroup recruited at the Children’s Hospital of Pennsylvania (CHOP), the scientists also evaluated past medications.

Median age at FA diagnosis was 14 years. Among the total group, 5.7% patients had a point mutation and 8.8% had diabetes. Participants with diabetes received that diagnosis at a median age of 27.

Point mutations were significantly more common among patients with diabetes than those who did not (13.9% vs. 4.9%). Participants with diabetes also were older and had more severe FA.

A statistical analysis showed that being older, having a point mutation and more severe FA were risk factors for developing diabetes.

Regarding the group treated at CHOP, the data also showed that 76% of patients with diabetes and current medication data used insulin, and 47% of those with the condition and past treatment information used metformin.

“Future studies will evaluate the pathophysiology [disease processes] of FA-related DM [diabetes] to inform screening practices and management decisions,” the scientists wrote.