{
  "url": "https://dantelabs.com/traits/reduced-circulating-ch50-activity",
  "trait": {
    "bundleId": "2026.10.17-8666dff2",
    "release": "2026-09-01",
    "slug": "reduced-circulating-ch50-activity",
    "id": "HP:0025434",
    "name": "Reduced circulating CH50 activity",
    "definition": "A diminished activity of the classical complement pathway as measured by the assay for 50% haemolytic complement (CH50) activity of serum.",
    "synonyms": [
      "Decreased total hemolytic complement activity",
      "Reduced CH50",
      "Reduced circulating 50% hemolytic complement (CH50) activity",
      "Reduced hemolytic complement activity"
    ],
    "systems": [
      {
        "slug": "abnormality-of-the-immune-system",
        "name": "Abnormality of the immune system",
        "url": "https://dantelabs.com/traits/abnormality-of-the-immune-system"
      }
    ],
    "broader": [
      {
        "slug": "abnormal-total-hemolytic-complement-activity",
        "name": "Abnormal total hemolytic complement activity",
        "url": "https://dantelabs.com/traits/abnormal-total-hemolytic-complement-activity"
      }
    ],
    "narrower": [],
    "genes": [
      {
        "slug": "c1qb",
        "symbol": "C1QB",
        "hgnc": "HGNC:1242",
        "name": "complement C1q B chain",
        "frequency": "obligate",
        "diseases": 1,
        "url": "https://dantelabs.com/genes/c1qb"
      },
      {
        "slug": "c5",
        "symbol": "C5",
        "hgnc": "HGNC:1331",
        "name": "complement C5",
        "frequency": "obligate",
        "diseases": 1,
        "url": "https://dantelabs.com/genes/c5"
      },
      {
        "slug": "c6",
        "symbol": "C6",
        "hgnc": "HGNC:1339",
        "name": "complement C6",
        "frequency": "obligate",
        "diseases": 1,
        "url": "https://dantelabs.com/genes/c6"
      },
      {
        "slug": "serping1",
        "symbol": "SERPING1",
        "hgnc": "HGNC:1228",
        "name": "serpin family G member 1",
        "frequency": "obligate",
        "diseases": 1,
        "url": "https://dantelabs.com/genes/serping1"
      },
      {
        "slug": "c4a",
        "symbol": "C4A",
        "hgnc": "HGNC:1323",
        "name": "complement C4A (Chido/Rodgers blood group)",
        "diseases": 1,
        "url": "https://dantelabs.com/genes/c4a"
      }
    ]
  }
}