Gene Relationship
GET /api/genes/SLIT2/relationships/genecombination_set?format=api
{
    "data": [
        {
            "type": "GeneCombination",
            "id": "612"
        },
        {
            "type": "GeneCombination",
            "id": "649"
        },
        {
            "type": "GeneCombination",
            "id": "673"
        },
        {
            "type": "GeneCombination",
            "id": "1251"
        }
    ]
}