Gene Relationship
GET /api/genes/LHX4/relationships/genecombination_set?format=api
{
    "data": [
        {
            "type": "GeneCombination",
            "id": "717"
        },
        {
            "type": "GeneCombination",
            "id": "845"
        },
        {
            "type": "GeneCombination",
            "id": "847"
        },
        {
            "type": "GeneCombination",
            "id": "1073"
        }
    ]
}