Skin Biopsy as a Diagnostic Tool for ATTRv Amyloid Neuropathy in the UK.

OBJECTIVE

Gene silencing therapy for ATTRv has revolutionised treatment. In minimally symptomatic, early neuropathic disease, skin biopsy can aid in the diagnosis of ATTRv-PN, assessing both amyloid deposition and IENFD. Our aim was to study the value of performing skin biopsies in the diagnosis of ATTRv-PN in UK patients and to assess the influence of this on accessing gene silencing treatment.

METHODS

Seventy-three patients had skin biopsies performed between July 2021 and October 2023. These were stained for amyloid, typed by immunohistochemistry, and analysed for IENFD.

RESULTS

The Thr60Ala (30%), Val122Ile (23%) and Val30Met (22%) variants represented the largest number of cases. Normal/equivocal neurophysiology was demonstrated in 78% of cases. 40% of patients had abnormal IENFD, 33% had positive amyloid and 16% had both. This allowed 33% of patients to start gene silencing therapy, 75% of whom had a preceding amyloid cardiomyopathy diagnosed.

CONCLUSIONS

Skin biopsy is a useful, minimally invasive method for diagnosing ATTRv-PN. It allowed a substantial number of patients to commence gene silencing treatment. As Thr60Ala and Val122Ile are the commonest TTR variants in the UK and patients often present with cardiomyopathy, early diagnosis of ATTRv-PN is critical for treatment decisions.