Currently, patients are treated with painkillers and antidepressants that do not treat the underlying nerve damage. Progression to amputation is not inevitable but is always a threat.
Problems may also occur in other organs, including the heart, kidneys, sex organs, eyes and digestive tract.
The incidence of diabetes, a condition in which the amount of glucose in the blood is too high, is increasing dramatically, with the World Health Organisation estimating that some 300 million people worldwide could be affected by 2025.
The causes of diabetic neuropathy are not fully understood but researchers investigating the effect of glucose on nerves believe it is likely to be a combination of factors.
Sangamo's Chief Medical Officer, Dr Dale Ando, said: "We have been greatly encouraged by Professor Tomlinson's data and have moved the programme into the clinic.
"The first phase of human trials will assess safety and examine the effects of a single treatment in one leg compared with a placebo treatment in the other leg."
The Diabetes and Glandular Disease Clinic in San Antonio, Texas, is involved in the clinical trials.
Dr Mark Kipnes, a clinical investigator for Sangamo and endocrinologist at the clinic, said: "Currently, there are no effective therapies available to treat this debilitating and frequent complication of diabetes and patients are generally prescribed painkillers to alleviate symptoms.
"We are excited to be involved in testing this novel approach that may potentially have a dramatic therapeutic effect in populations of patients already suffering from neuropathy and those that are at risk of developing it."