def gpx4_patients(json_patients):
    """Return all patients with variants in GPX4 gene"""

    patient_list = []

    for patient in json_patients:
        gpx4 = False
        if patient.get("genomicFeatures") is None:
            continue
        for g_feature in patient["genomicFeatures"]:
            if g_feature["gene"]["id"] == "GPX4":
                gpx4 = True
        if gpx4:
            patient_list.append(patient)
    return patient_list