Insurers fund Ashkenazi panels while Tahitian carriers wait

On 8 October, a team of population geneticists reported a kidney-disease variant found in 2.22% of the people sampled in French Polynesia. The variant, FAN1 p.Trp707*, causes karyomegalic interstitial nephritis, a globally ultrarare disease usually ending in renal failure. Its allele frequency across 896 unrelated French Polynesians came to 1.11%. The Genome Aggregation Database, gnomAD v4.1, pools more than 800,000 genomes and exomes and lists the variant at a frequency of 0. The American College of Medical Genetics and Genomics points to databases such as gnomAD to inform screening panels for founder populations.

The team dated the founding of Tahiti from 581 Society Islanders, the largest island sample in the study. The effective population bottomed at 837 people 34 generations ago, about 1069 AD at 28 years a generation. Radiocarbon estimates for the settlement of the Society Islands span roughly 1025 to 1120 AD. Exponential growth followed the bottleneck. The authors scored shared inherited segments between islanders, a measure tied to recessive disease risk. The score came out at least an order of magnitude higher in Polynesia than in Finland, a widely studied founder population.

Hawaiʻi and Rapa Nui, about 7,000 km apart, share the longest common path through the settlement sequence. In 2,500 bootstrapped trees, Hawaiʻi paired with Rapa Nui in 61%, with Mangareva in 10.45% and with the Marquesas in 2.75%. The authors interpret the result as a voyaging group with roots in Mangareva settling the 2 remotest islands of the triangle. They name that group Holomoana Nui, great ocean voyaging. In 1966 Robert Green placed Hawaiian, Mangarevan and Marquesan in a proto-Marquesic subgroup, with Rapa Nui as a close outlier.

Tier 3 of the ACMG carrier screening guidance applies to conditions with a carrier frequency of 1 in 200 or more, or 0.5%. The 3 variants measured in French Polynesia exceed that threshold 4 to 7 times. ADAMTSL4 p.Arg746His, a cause of early lens dislocation, shows a carrier frequency of 2.46%. PDE6B p.Ala733Pro, a cause of progressive vision loss, comes in at 3.68%. FAN1 comes to 2.22%. The authors designed the French Polynesian sampling to be representative of the territory.

Many large US insurers adhere to the ACMG guidelines. Aetna's medical policy, last reviewed on 18 August 2026, lists 14 conditions for preconception or prenatal carrier screening of patients with Ashkenazi Jewish ancestry. Insurers pay for gene panels. A panel lists variants with a measured population frequency. For Native Hawaiians and other Pacific Islanders, however, the authors write that the frequencies of founder disease variants remain largely unknown. Native Hawaiians in the US already outnumber the Amish nearly 2 to 1, a community well studied for its population-specific conditions.

To the authors, the broad Native Hawaiian and Pacific Islander label gives a carrier screening programme about as much resolution as German ancestry would give an Amish or Ashkenazi patient. Hawaiians descend from the last link in a series of founder events and likely show clinically important alleles at frequencies unlike those of Samoans further west. Their paper urges researchers to distinguish island populations in founder-mutation studies and in the ACMG screening guidance.

In French Polynesia, a retrospective study of end-stage kidney disease in patients under 45 found an identifiable genetic cause in 32% of cases. About 75% of that cohort had kidney failure unrelated to diabetes, hypertension or obesity. FAN1 p.W707X was described in 2021 as a recurrent South Pacific variant with an origin earlier than AD 1800. Because FAN1 is part of the Fanconi anaemia DNA-repair pathway, the authors link its weight in population health to radiation from French nuclear tests still present in the Tuamotu environment.

The French Polynesian genomes came largely from the Maʻi uʻu study, an epidemiological survey of gout. Those samples supply carrier frequencies for 3 recessive diseases in the new paper. The team deposited its previously unpublished sequences in the European Genome-phenome Archive under accession EGAS50000002085, with controlled access. The scope clause of an informed-consent form records a participant's authorisation for later uses of a sample. An ethics committee in Suva examines the consent form against the accompanying protocol.

On a Pacific consent set handled by Huri, a reviewer compared the target text with its back-translation and flagged a phrase. The back-translation gave families for a phrase meaning entitlements in the English source. The reviewer had taken the target word for a near-identical spelling meaning families and asked whether the translation or the back-translation was wrong. A fluency check on the target sentence found it grammatical under 2 readings. In a genetics consent, family is a working term, since a carrier result bears on a participant's relatives.

The ethics statement of the paper commits its authors to Indigenous data sovereignty and to benefit-sharing with participants. The Global Indigenous Data Alliance published the CARE Principles for Indigenous Data Governance in 2019. The Data Science Journal printed them in 2020. The 4 principles are Collective benefit, Authority to control, Responsibility and Ethics. On Rapa Nui, the Mata Ki Te Rangi Foundation helped the team collect 12 new genomes.

Polynesian-specific frequencies come out higher again. FAN1 rises to 1.49% among the 537 people with Polynesian ancestry on the 2 copies of the chromosome at the variant, against 1.11% across the full sample. PDE6B rises to 2.62% among 535 such people, from 1.84% overall. Excluding second-degree relatives left 896 individuals for the headline figures. The authors counted them regardless of self-reported ethnicity to reflect the current risk to islanders.