March 2026 Research Update

This month added more detail that gene-silencing treatments can show similar patterns of benefit across different ATTRv genetic backgrounds, although the subgroup results are still based on smaller numbers. In an exploratory Phase 3 analysis, eplontersen lowered blood transthyretin (TTR) levels and measures of neuropathy and quality of life were generally preserved or improved across Val30Met and non-Val30Met groups, including both earlier- and later-onset disease. A separate post hoc analysis suggested vutrisiran outcomes in East Asian participants moved in the same direction and size as the full HELIOS-A trial population, with a broadly similar safety picture. [1] [2]

For eplontersen, the report compared outcomes with a historical placebo group and described quality-of-life scores improving with eplontersen while placebo worsened, alongside generally maintained neuropathy function over about 15 months. [1]

For vutrisiran, the East Asian subgroup analysis reported changes in neuropathy, walking, and quality-of-life measures that matched the overall trial direction and magnitude, while noting the subgroup was small (33 people). The report also noted adverse events were broadly similar to the overall trial population, and fewer deaths and fewer treatment-related or serious adverse events than the external placebo group used for comparison. [2]

A separate report of two people with a rare TTR variant (His90Asn/His110Asn) described marked neuropathy improvement and weight gain after 9 to 12 months of patisiran, with no safety concerns reported in these two cases. Because these are individual cases and the variant is still considered uncertain in some classification systems, this mainly serves as an early signal rather than a generalizable result. [3]

For patients, these studies mainly add reassurance that the direction of benefit seen in large ATTRv polyneuropathy trials may extend across different variants and across earlier- and later-onset groups, but the details for smaller subgroups still need confirmation. The eplontersen and vutrisiran results are human clinical data, but they are presented here as exploratory or post hoc subgroup analyses, which can be less certain than the main trial results. The patisiran report is limited to 2 people and is most useful for understanding what might be possible for rare variants, not for predicting typical outcomes. [1] [2] [3]

This month, several studies focused on whether ATTRv changes can be detected earlier or more clearly by combining measurements rather than relying on a single test. Across studies, signals of early nerve or heart involvement were seen even in some people without clear symptoms, but the proposed tools are not yet proven as stand-alone ways to predict who will become ill. The most consistent message was that multiple kinds of information (imaging, nerve measures, and blood markers) may capture different parts of ATTRv and could complement each other. [4] [5] [6]

One cross-sectional study using a heart nerve imaging scan (123I-mIBG) found reduced heart-to-mediastinum ratios not only in symptomatic ATTRv patients but also in asymptomatic carriers, suggesting early changes in the heart's sympathetic nerves before obvious symptoms. In the same study, about half of asymptomatic carriers also showed reduced small-fiber nerve density in skin biopsies, pointing to early nerve involvement that standard nerve tests may miss. [4]

Blood biomarker studies were mixed, which helps clarify what each marker may and may not represent. Serum peripherin (a protein linked to nerve axon damage) was elevated in both presymptomatic and symptomatic ATTRv groups compared with healthy controls, and it separated ATTRv from controls with an AUC of 0.83. In contrast, serum neurofilament light chain (sNfL) was higher in people labeled as having autonomic neuropathy, but after accounting for age and co-existing peripheral neuropathy, sNfL did not independently point to autonomic involvement, partly because there were few cases with isolated autonomic symptoms. [5] [6]

Two echocardiography-focused studies suggested that more detailed heart measurements may reveal ATTR-related patterns earlier than traditional single measurements. In TTR Val142Ile carriers from a biobank, a machine-learning model using multiple strain (heart muscle movement) features separated carriers from non-carriers better than any single strain measure alone. In people already diagnosed with ATTR cardiomyopathy, adding left atrial reservoir strain (a measure of how the left atrium stretches) reduced the number of "indeterminate" filling-pressure results and increased the proportion labeled as having elevated filling pressures, while restrictive filling remained uncommon overall and more common in wild-type ATTR than hereditary ATTR. [7] [8]

For patients and families, these studies strengthen the idea that ATTRv can affect nerves and the heart before symptoms become obvious, and that early signals may show up in different places depending on the person. The work on 123I-mIBG scans, skin biopsy, and blood markers may matter later if they are confirmed to reliably identify early disease or track change over time, but they are not yet presented as definitive tests for individual prediction. The echocardiography findings add to research aimed at spotting subtle heart patterns earlier, especially in Val142Ile carriers, but the machine-learning approach and the strain measures need prospective testing before they can be considered dependable for routine use. [4] [5] [6] [7] [8]

This month highlighted how variable ATTRv can look at first, and why diagnosis often depends on putting multiple clues together rather than expecting one classic pattern. Across clinical cohorts, registries, and case reports, nerve symptoms were commonly front-and-center, while heart involvement could be present but not always obvious from basic tests. Several reports also described unusual presentations affecting cranial nerves or mimicking other neurologic diseases, which adds to the picture of ATTRv as a condition that can be missed if clinicians and patients expect only typical neuropathy or typical cardiomyopathy. [9] [10] [11] [12] [13]

In a cohort of 63 people diagnosed through cardiology and neurology clinics, most diagnoses occurred in neurology settings, and peripheral neuropathy and autonomic symptoms were the most common red flags at diagnosis. The report also emphasized that significant heart involvement can still be present even when the diagnostic path starts in neurology, and that the absence of certain ECG patterns did not necessarily rule out ATTR. [9]

A nationwide Austrian registry update described a wide range of TTR variants (23 variants across 100 people) and both symptomatic and asymptomatic carriers, with some variants clustering in specific regions. It also reported a rising number of Val142Ile carriers, reinforcing that who gets identified can change over time as genetic testing becomes more common. [10]

Several smaller reports underscored that ATTRv can involve parts of the nervous system that are not always emphasized, and that biopsies can be negative even when ATTRv is present. A letter on Ile127Val carriers in Brazil reported cranial nerve involvement in 3 of 31 people, suggesting this may be more frequent in that regional group and helping distinguish these symptoms from bulbar motor neuron disease. A report of two Chinese patients and a review of published Val50Met nerve biopsies found no clear relationship between age at onset and whether amyloid is seen on sural nerve biopsy, and one patient had nerve fiber loss without amyloid detected. [12] [13]

A single case report described hereditary ATTRv (Val142Ile) presenting with features that mimicked amyotrophic lateral sclerosis (ALS), with nerve testing showing widespread denervation alongside a length-dependent neuropathy pattern. The report illustrates how ATTRv can enter the differential diagnosis when symptoms look like other neurologic conditions, even when autonomic or other organ involvement is not prominent. [11]

For patients, these reports mainly add context for why ATTRv can take time to recognize: symptoms can start in the nerves, the heart can be involved quietly, and some tests (like nerve biopsy) may not show amyloid even when the disease is present. The registry and clinic-based cohort data may matter now for understanding what patterns are commonly seen at diagnosis and which variants are being identified in different regions, but they do not by themselves predict an individual's course. The case reports and small regional cohorts are early, descriptive evidence; they are most useful for expanding awareness of less typical presentations that could otherwise be mistaken for other neurologic problems. [9] [10] [12] [13] [11]