Academic Unit of Medical Genetics, St. Mary's Hospital, Manchester, UK.
World J Pediatr. 2013 May;9(2):179-81. doi: 10.1007/s12519-011-0280-x. Epub 2011 Nov 21.
Mosaic trisomy 18 has a wide phenotypic spectrum ranging from near normal to early death. We report two cases that add to our knowledge of the disease.
Patient 1 was a girl with a tracheoesophageal fistula, horse-shoe kidneys and a ventricular septal defect. Karyotyping of her lymphocytes showed complete trisomy 18. Due to her milder phenotypes, skin fibroblasts were karyotyped. Patient 2 was a boy with biventricular hypertrophic cardiomyopathy, patent ductus arteriosus, ventricular and atrial septal defects and significant feeding problems.
Karyotyping of the skin and lymphocytes in patients 1 and 2 respectively revealed trisomy 18 mosaicism. Both children had only mild learning problems and were generally healthy with satisfactory growth. Patient 1 illustrates the possibility of significant discrepancy between the levels of trisomic cells in skin fibroblasts and lymphocytes leading to misdiagnosis. This finding has significant implications in medical management and counselling. Hypertrophic cardiomyopathy in patient 2 is recognized as a novel finding for this condition.
There is the possibility of good outcome for patients with mosaic trisomy 18, even in the presence of multiple congenital anomalies.
镶嵌型三体 18 具有广泛的表型谱，从近乎正常到早期死亡不等。我们报告两例病例，增加了我们对该病的认识。
患者 1 为一名患有气管食管瘘、马蹄肾和室间隔缺损的女孩。其淋巴细胞的核型分析显示完全三体 18。由于她的表型较轻微，对其皮肤成纤维细胞进行了核型分析。患者 2 为一名患有双侧心室肥厚型心肌病、动脉导管未闭、室间隔和房间隔缺损以及严重喂养问题的男孩。
分别对患者 1 和 2 的皮肤和淋巴细胞进行核型分析，发现均存在三体 18 镶嵌现象。两名患儿仅有轻度学习问题，整体健康状况良好，生长满意。患者 1 表明皮肤成纤维细胞和淋巴细胞中三体细胞水平存在显著差异，可能导致误诊。这一发现对医疗管理和咨询具有重要意义。患者 2 的肥厚型心肌病是该病的一种新发现。
即使存在多种先天性异常，镶嵌型三体 18 患者也有可能获得良好的预后。
