What the Years Before Diagnosis Reveal in hATTR Polyneuropathy

Key Takeaways:

• The typical patient carries symptoms for years – often 3 to 6 – and collects 1 or more incorrect diagnoses before hATTR polyneuropathy is identified.
• Features patients describe in hindsight – bilateral carpal tunnel releases years earlier, fuzzy then numb fingertips and feet, repeated nerve studies that never named the disease – are retrospective red flags when they cluster.
• A relative's diagnosis is frequently the turning point. Treat a suggestive family history as an active diagnostic signal, not a footnote.

In many cases, the diagnosis of hereditary transthyretin amyloidosis with polyneuropathy (hATTR-PN) is often reconstructed backward. By the time a pathogenic TTR variant is confirmed, the patient has usually lived with the disease for years – in non-endemic regions, the diagnosis is typically delayed by 3 to 4 years, and hATTR-PN is suspected at only 26 to 38% of initial evaluations. These years are not just a delay in reaching the right diagnosis. During this time, neuropathy often continues to progress while patients undergo multiple evaluations and treatment for alternative diagnoses.¹

What patients describe about those intervening years is not a vague prodrome. It is a sequence of discrete, documentable events, each of which reads in hindsight as a missed signal.

Symptoms dismissed as aging

The earliest symptoms are easy to file under something else. In one interview study, patients reported worsening symptoms for nearly 6 years, on average, before diagnosis, with early sensory changes attributed to aging, injury, or an existing comorbidity.²

One patient's own account captures the ambiguity – he recalls that his "fingertips were feeling fuzzy" and that everyday tasks with his hands were "getting harder" at age 49, changes he was sure were "just aging.”3

Another patient, recalling the same disorientation, simply asked, "What the heck is going on?”²

For the clinician, the lesson is that a length-dependent sensory complaint dismissed as age-related may be the presentation that later proves to be early hATTR-PN.

The bilateral carpal tunnel clue

Among the events that recur in these histories, bilateral carpal tunnel release stands out. The same patient underwent carpal tunnel surgery on both wrists – "first one wrist, wait a while, then the other" – years before amyloidosis was considered.³

That pattern is diagnostically loud: in a cohort comparing hATTR-PN with chronic idiopathic axonal polyneuropathy, carpal tunnel syndrome (CTS) was present in 87% versus 39% of patients and was bilateral in nearly every affected case, though the small, single-variant sample warrants caution in reading the exact proportions.⁴

A wrist release performed years earlier is not incidental history – it is a data point that belongs in the neuropathy workup. Although bilateral carpal tunnel syndrome is common, it becomes much more meaningful when it precedes a progressive neuropathy or occurs with other features suggestive of hATTR amyloidosis.

Misdiagnoses before the answer

Before the correct label, most patients accumulate an incorrect one. Multiple misdiagnoses are reported in 20 to 40% of cases, and the differential that patients are handed includes Charcot-Marie-Tooth disease (CMT), among other inherited and inflammatory neuropathies.^1,5

One patient was told he had CMT and lived with the label for years, though, as he put it, his "gut told [him] that the CMT diagnosis was bogus.” When he asked for genetic testing, he was told the disease was "far too rare" and that he "couldn't possibly have that.” The cost of that interval is not abstract; as one patient in a focus group put it, "I lost 3 years of treatment.”^3,6

Family history as a signal

The turning point in many accounts is not a test result but a relative's diagnosis. For one patient, the recognition that his own symptoms might be hereditary arrived when his older brother was diagnosed – "my first bombshell dropped" – and it still took 2 more misdiagnoses before, in 2014, he was "finally diagnosed positive by a genetic test," a result that, he wrote, "confirmed what I already knew.”³

Family history is easy to overlook. In non-endemic regions, 52 to 77% of patients present with no known family history of the disease, so its absence proves little. But its presence should move the needle hard. Even when hATTR amyloidosis runs in a family, the diagnosis may not be obvious. Relatives may have been misdiagnosed, developed symptoms much later in life, or presented with predominantly cardiac disease, making the family history initially appear negative.¹

In the red-flag cohort, a first-degree family history was reported by 60% versus 9% of hATTR-PN patients versus comparison patients. Demographic assumptions compound the delay. One patient diagnosed in midlife, whose father had died of the disease, recalls being told she was "too young," a reminder that "young does not mean immune.” Even within the same family, age at symptom onset and the pattern of organ involvement can vary considerably, so 1 affected relative may not resemble another.^3,4

Practically, this argues for treating a suggestive family history as an active prompt – one item in a formal suspicion index that, met alongside features such as bilateral CTS or autonomic dysfunction, should trigger TTR genetic testing rather than another year of watchful waiting. Earlier recognition of these clinical patterns has become increasingly important as disease-modifying therapies are now available, making timely diagnosis more meaningful than ever.¹