Gene Relationship
GET /api/genes/PGAM4/relationships/genecombination_set?format=api
{
    "data": [
        {
            "type": "GeneCombination",
            "id": "222"
        }
    ]
}
              GET /api/genes/PGAM4/relationships/genecombination_set?format=api
{
    "data": [
        {
            "type": "GeneCombination",
            "id": "222"
        }
    ]
}