Pozza Elise, Verdin Hannah, Deconinck Hilde, Dheedene Annelies, Menten Björn, De Baere Elfride, Balikova Irina
Department of Ophthalmology, Children Hospital Queen Fabiola, Brussels, Belgium.
Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium University of Ghent, Ghent, Belgium.
Eur J Med Genet. 2020 May;63(5):103918. doi: 10.1016/j.ejmg.2020.103918. Epub 2020 Mar 19.
Congenital microcoria (MCOR) is an eye anomaly characterized by a pupil with diameter below 2 mm, and is caused by underdevelopment or absence of the dilator muscle of the pupil. Two types have been described: a recessive, syndromic (Pierson syndrome OMIM 609049) and a dominant, isolated form (MCOR syndrome OMIM 156600). Fares-Taie and colleagues described inherited microdeletions in chromosome band 13q32.1 segregating with dominant microcoria in several families. The GPR180 gene is located within the smallest commonly deleted region and encodes a G protein-coupled receptor involved in smooth muscle cells growth. We here describe a patient with isolated, non-syndromic MCOR. The patient presented with a blue iris and small pupils, non-reactive to cycloplegic agents. Her mother had a milder ocular phenotype, namely a blue iris with hypoplastic crypts and mild myopia. We present a detailed clinical examination and follow up. DNA from the index patient was analyzed for the presence of chromosomal imbalances using molecular karyotyping. The genetic test revealed a small duplication of chromosome band 13q32.1. The duplication affected a 289 kb region, encompassing 11 genes including GPR180. Interestingly, the patient displays only MCOR in contrast to patients with the reciprocal deletion who present with MCOR and iridocorneal angle dysgenesis. This genetic anomaly was inherited from the mother who carries the duplication in mosaic form, which should be considered when offering genetic counselling. In summary, we describe the first 13q32.1 duplication encompassing GPR180 associated with MCOR.
先天性小瞳孔症（MCOR）是一种眼部异常疾病，其特征为瞳孔直径小于2毫米，由瞳孔开大肌发育不全或缺失引起。该病已被描述为两种类型：隐性综合征型（皮尔逊综合征，OMIM 609049）和显性孤立型（MCOR综合征，OMIM 156600）。法雷斯 - 泰伊及其同事描述了13q32.1染色体带中的遗传性微缺失，在几个家族中与显性小瞳孔症共分离。GPR180基因位于最小的常见缺失区域内，编码一种参与平滑肌细胞生长的G蛋白偶联受体。我们在此描述一名患有孤立性、非综合征性MCOR的患者。该患者表现为蓝色虹膜和小瞳孔，对睫状肌麻痹剂无反应。她的母亲有较轻的眼部表型，即蓝色虹膜伴发育不全的隐窝和轻度近视。我们进行了详细的临床检查和随访。使用分子核型分析对索引患者的DNA进行染色体失衡检测。基因检测发现13q32.1染色体带存在小的重复。该重复影响了一个289 kb的区域，包含11个基因，包括GPR180。有趣的是，与携带相互缺失且表现为MCOR和虹膜角膜角发育异常的患者相比，该患者仅表现出MCOR。这种基因异常是从母亲那里遗传而来的，母亲以嵌合形式携带该重复，在提供遗传咨询时应予以考虑。总之，我们描述了首例与MCOR相关的包含GPR180的13q32.1重复。
