You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Gene"].

Please return the output as a JSON object of the format: {"Gene": ["SSX", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Trisomy 1 in a case of a missed abortion. Most chromosomal trisomies lead to miscarriages. In all trisomies, trisomy 1 is the most rare case. We herein present a patient who demonstrated a gestational sac and a yolk sac on transvaginal ultrasound. However, at 53 days of gestation, the pregnancy was lost with a diagnosis of a blighted ovum. A D_C was recommended and performed. A cytogenetic analysis from chorionic villi demonstrated a 47,XX,+1 chromosome complement in all 100 cells. Regarding full trisomy 1, there has only been one case report of a preembryo and two case reports in a clinically recognized pregnancy to date.
{"Gene": []}