{
  "resourceType": "StructureDefinition",
  "url": "https://example.org/fhir/StructureDefinition/MyExtension",
  "name": "MyExtension",
  "status": "draft",
  "fhirVersion": "5.0.0",
  "kind": "complex-type",
  "abstract": false,
  "context": [
    {
      "type": "element",
      "expression": "Patient.identifier"
    }
  ],
  "type": "Extension",
  "baseDefinition": "http://hl7.org/fhir/StructureDefinition/Extension",
  "derivation": "constraint",
  "differential": {
    "element": [
      {
        "id": "Extension",
        "path": "Extension",
        "short": "aadhar Number",
        "definition": "Aadhar Number addition",
        "comment": "Aadhar num"
      },
      {
        "id": "Extension.extension",
        "path": "Extension.extension",
        "max": "0"
      },
      {
        "id": "Extension.url",
        "path": "Extension.url",
        "fixedUri": "https://example.org/fhir/StructureDefinition/MyExtension"
      },
      {
        "id": "Extension.value[x]",
        "path": "Extension.value[x]",
        "type": [
          {
            "code": "string"
          }
        ],
        "meaningWhenMissing": "Provide Aadhar Number ",
        "patternString": "^\\d[12]$",
        "maxLength": 12,
        "binding": {
          "strength": "required",
          "description": "Mandate Provide 12 digit Aadhar number"
        }
      }
    ]
  }
}