{
  "title": "Proband Phenotypic Constellation vs Syndromic Differential Matrix",
  "description": "Cross-referencing observed clinical HPO findings against competing pediatric rare disease and cancer predisposition syndromes.",
  "phenotypes": [
    {
      "feature": "Rhabdomyosarcoma (RMS)",
      "hpo": "HP:0002859",
      "mva_syndrome_match": "High (Hallmark embryonal malignancy in MVA Type 1 & 3)",
      "mva_genes": "BUB1B, TRIP13, DICER1, TP53",
      "competing_syndromes": "Li-Fraumeni (TP53), DICER1 Syndrome, Costello Syndrome (HRAS), Beckwith-Wiedemann (11p15)",
      "molecular_mechanism": "Mitotic checkpoint leakage triggers chromosome 15/11/8 aneuploid nondisjunction, leading to somatic loss of heterozygosity (LOH) and oncogenic transformation of skeletal myoblasts.",
      "discriminatory_power": "Very High: Isolated RMS doesn't cause nephrocalcinosis or premature IUGR, but MVA links all three."
    },
    {
      "feature": "Congenital Nephrocalcinosis",
      "hpo": "HP:0000121",
      "mva_syndrome_match": "High (Characteristic in MVA Type 2 and centrosomal ciliopathies)",
      "mva_genes": "CEP57, WT1, CEP192",
      "competing_syndromes": "Dent Disease (CLCN5), Bartter Syndrome (SLC12A1), Primary Hyperoxaluria, Familial Hypomagnesemia",
      "molecular_mechanism": "Centrosomal dysfunction (CEP57/CEP192) impairs primary cilia formation in renal collecting duct epithelium, causing calcium phosphate precipitation and medullary calcification.",
      "discriminatory_power": "Critical: Distinguishes MVA2/centrosomal etiology from standard pediatric sarcoma syndromes."
    },
    {
      "feature": "Intrauterine Growth Restriction (IUGR, 1.0 kg)",
      "hpo": "HP:0001518",
      "mva_syndrome_match": "Pathognomonic (Severe primordial growth retardation)",
      "mva_genes": "BUB1B, CEP57, CENPE, CENPF, CEP192",
      "competing_syndromes": "Silver-Russell Syndrome (11p15), Meier-Gorlin Syndrome (ORC1), Seckel Syndrome (ATR)",
      "molecular_mechanism": "Systemic cellular attrition due to mitotic catastrophe and p53-mediated apoptosis in rapidly dividing embryonic stem cells.",
      "discriminatory_power": "High: Corroborates global embryonic cell cycle failure."
    },
    {
      "feature": "Premature Delivery (32 Weeks)",
      "hpo": "HP:0001622",
      "mva_syndrome_match": "Consistent (Placental insufficiency & fetal distress)",
      "mva_genes": "BUB1B, CEP57",
      "competing_syndromes": "Maternal vascular malperfusion, Pre-eclampsia",
      "molecular_mechanism": "Aneuploid mosaicism within trophoblast and placental villi impair maternal-fetal gas and nutrient exchange.",
      "discriminatory_power": "Moderate: Supports placental aneuploid involvement."
    },
    {
      "feature": "Parental Recurrent Miscarriages",
      "hpo": "HP:0200067",
      "mva_syndrome_match": "Strong (Familial segregation defect & meiotic instability)",
      "mva_genes": "BUB1B, TRIP13, MAD1L1",
      "competing_syndromes": "Balanced reciprocal translocations, Inversions, Antiphospholipid Syndrome",
      "molecular_mechanism": "Heterozygous carrier parents can exhibit subclinical meiotic chromosome missegregation, generating nonviable aneuploid zygotes resulting in recurrent first-trimester spontaneous abortions.",
      "discriminatory_power": "Very High: Points specifically to germline spindle checkpoint vulnerability."
    },
    {
      "feature": "Skeletal Muscle Atrophy & Low Mass",
      "hpo": "HP:0003202",
      "mva_syndrome_match": "Consistent (Myoblast exhaustion & cachexia)",
      "mva_genes": "BUB1B, CENPF, MAD1L1",
      "competing_syndromes": "Spinal Muscular Atrophy (SMN1), Congenital Myopathies",
      "molecular_mechanism": "Impaired myoblast proliferative expansion during myogenesis combined with tumor-associated catabolic microenvironment.",
      "discriminatory_power": "Moderate: Secondary consequence of both syndromic myogenesis defect and sarcoma burden."
    }
  ]
}