The measured pain channelopathies anchor the firing-threshold direction, and one inherited measured gamma grounds the nociceptor that sec.21 and sec.22 read — the DNA-emergence inheritance, made explicit

Two measured DNA directions bracket the lever map and prove the axis is real, not an analogy. A Na_V1.7 (SCN9A) loss-of-function drives the firing threshold to infinity — congenital insensitivity to pain, no pain under any circumstance; a gain-of-function lowers it — inherited erythromelalgia and paroxysmal extreme pain disorder. The realised analgesic (a Na_V1.8 closed-state stabiliser, approved 2025) sits on the SAME axis, pushed the protective way. And the nociceptor that sec.21 and sec.22 read emerges from one inherited measured promoter gamma (form <- gamma) — so the map, the disease dynamics, and the cell all sit on one DNA grounding.

The firing-threshold frame the analgesic map (sec.21) and the neuropathic-pain dynamics (sec.22) use is anchored at both ends by measured human biology. The nociceptor firing threshold is the pain knob: lower it and there is more pain, raise it and there is less. A Na_V1.7 loss-of-function sends the threshold to infinity (the gate never opens) and the measured phenotype is congenital insensitivity to pain (Cox 2006); a gain-of-function lowers or sustains the gate and the measured phenotypes are inherited erythromelalgia (Drenth 2005) and paroxysmal extreme pain disorder (Fertleman 2006; Estacion 2008); an NTRK1 loss-of-function removes the nociceptor developmental arm (CIPA, Indo 1996). The realised analgesic move, a Na_V1.8 (SCN10A) closed-state stabiliser, raises the threshold and is the FDA-approved non-opioid suzetrigine (2025-01-30). These monogenic entities are gene-key and owned by the rare-disease volume (disease_wp); this volume owns only the threshold DYNAMICS and cross-references that volume for the named entity. The second half makes the DNA-emergence inheritance explicit: the nociceptor lineage emerges from one inherited measured promoter gamma = −mean(NN stacking ΔG, SantaLucia 1998), read on the shared R19 Organ primitive (presence threshold = spinodal(gamma), emergence order = argsort spinodal, relative dwell ~ gamma^1.5) exactly the DNA volume rule (form <- gamma; 4D DNA Blueprint, DOI 10.5281/zenodo.20471407). That inherited gamma is bit-for-bit the measured atlas gamma the sec.21 map and sec.22 dynamics read, so all three sit on one grounding. The channelopathy directions are [V/F] anchored to measured phenotypes; gamma is measured [V], never fitted; every clinical magnitude is [O].

The measured channelopathies, read as firing-threshold directions:

The two DNA directions bracket the lever map: a LOF that drives the threshold to infinity ABOLISHES pain (CIP), and a GOF that lowers it CAUSES spontaneous pain (IEM/PEPD). The realised analgesic (Na_V1.8 closed-state stabiliser) sits on the SAME axis, pushed the protective way. So 'raise the firing threshold' is not an analogy — it is the measured pain axis, and the three levers are three ways onto it.

The DNA-emergence grounding (made explicit)

The whole chain stands on one inherited fact: the measured promoter gamma of a master gene, read on the shared R19 switch, emerges the cell. This volume already used it (sec.12 sensory-organ-4d, sec.20 atlas); here it is made explicit for the nociceptor lineage. For each lineage gene the element emerges via this volume own R19 Organ primitive — presence threshold = spinodal(γ), relative dwell ~ γ^1.5 — and the inherited gamma is bit-for-bit the measured atlas gamma that the sec.21 map and sec.22 dynamics read (grounding match: true). One grounding, three readings.

Emergence order (argsort spinodal, the DNA gene-clock rule): TRPA1 &lt; ETV1 &lt; SCN9A &lt; TRPV1 &lt; PIEZO2 &lt; RUNX3 &lt; NTRK1 &lt; NTRK3 &lt; PRDM12. The order is the morphogen/threshold spinodal, not a fitted ranking; gamma is measured and only the inherited grounding is used.

The plan for the existing chapters (sec.00–sec.20) is the same inheritance, stated forward: every chapter that names a master gene already carries its measured gamma in the sec.20 atlas, so the DNA-emergence grounding is applied by reading that gamma on the R19 Organ/Neuron primitive rather than asserting the cell — the route this section demonstrates for the nociceptor lineage and the route sec.12/sec.17 already take for the sensory organs and the spinal cord. gamma is measured [V], never fitted; identity and order are owned by the DNA volume; this volume emerges via R19.