Why It's Impossible to Treat Chronic Gut Dysfunction at the Bacterial Level — Layer 4: The Genetics — A Susceptibility Map, Not a Diagnosis

This is where the field gets it most wrong, in both directions. The conventional side dismisses genetics as irrelevant. The functional side treats a heterozygous MTHFR variant like a death sentence and hands the patient 5-methylfolate supplements as if that&#8217;s the answer. Both are wrong. What genetic testing actually tells you A genetic panel &#8212; whether from 23andMe, AncestryDNA, or a clinical whole genome sequence &#8212; gives you the specific variants you inherited at each of thousands of locations in your DNA. Certain variants affect how well specific enzymes work. Some variants reduce enzyme activity by 30%. Some by 70%. Some have no effect at all. What genetics does not tell you is whether any of this matters for your current symptoms. A variant that reduces an enzyme&#8217;s activity by 70% might be fully compensated for by your lifestyle, your diet, and your other pathways. Or it might be the hidden weakness that, when pushed by the right stressor, collapses everything downstream. Genetics is a susceptibility map. It tells you where the thin ice is. It doesn&#8217;t tell you whether you&#8217;re currently standing on it. Here is what the genetic data actually adds when you overlay it on the mitochondrial and immune findings: MTHFR C677T homozygous (TT) &#8594; ~70% reduction in an enzyme called methylenetetrahydrofolate reductase. What this enzyme does: it pro