{
  "url": "https://dantelabs.com/traits/glomerular-basement-membrane-duplication",
  "trait": {
    "bundleId": "2026.10.19-9814e911",
    "release": "2026-09-01",
    "slug": "glomerular-basement-membrane-duplication",
    "id": "HP:0020109",
    "name": "Glomerular basement membrane duplication",
    "definition": "Glomerular basement membrane duplication (GBM-DP) can be seen with Periodic acid-Schiff and silver stains. This appearance results from the presence of subendothelial deposits and the so-called mesangial interposition whereby mesangial cells, infiltrating mononuclear cells, or even portions of endothelial cells interpose themselves between the endothelium and basement membrane, with new, inner GBM-like material being laid down. This produces a double contour or tram-track appearance on light or electron microscopy. This finding often reflects splitting of the lamina densa and is associated with disease processes such as membranoproliferative glomerulonephritis, transplant glomerulopathy, and diabetic nephropathy.",
    "synonyms": [
      "Double contour of glomerular basement membrane",
      "GBM duplication",
      "GBM reduplication",
      "Tram-track appearance of GBM"
    ],
    "systems": [
      {
        "slug": "abnormality-of-the-genitourinary-system",
        "name": "Abnormality of the genitourinary system",
        "url": "https://dantelabs.com/traits/abnormality-of-the-genitourinary-system"
      }
    ],
    "broader": [
      {
        "slug": "abnormal-glomerular-basement-membrane-morphology",
        "name": "Abnormal glomerular basement membrane morphology",
        "url": "https://dantelabs.com/traits/abnormal-glomerular-basement-membrane-morphology"
      }
    ],
    "narrower": [],
    "genes": [
      {
        "slug": "pld4",
        "symbol": "PLD4",
        "hgnc": "HGNC:23792",
        "name": "phospholipase D family member 4",
        "frequency": "obligate",
        "diseases": 1,
        "url": "https://dantelabs.com/genes/pld4"
      }
    ]
  }
}