Sánchez-Herrero Ángeles, Carmona-Talavera Diego, García-Verdevio M Elia, Hernando-Espinilla Amaya, Estañ-Capell Nuria
Cytogenetics and Molecular Biology Unit, Department of Clinical Analysis, Hospital Universitario Doctor Peset, Valencia, Spain.
Department of Gynecology and Obstetrics, Hospital Universitario Doctor Peset, Valencia, Spain.
J Pediatr Genet. 2020 Nov 19;12(1):64-68. doi: 10.1055/s-0040-1721076. eCollection 2023 Mar.
Chromosomal mosaicism is defined as the presence of two or more different cell lines in an organism that originate from the same embryo. Trisomy of chromosome 5 is one of the most severe forms of autosomal trisomy and only seven cases of mosaic trisomy 5 have been reported to date. Mosaicism at prenatal level constitutes a challenge in genetic counseling, particularly in the case of mosaic trisomy 5, due to its low incidence. We report the case of a girl with a prenatal diagnosis of mosaic trisomy 5. The pre- and postnatal genetic tests (noninvasive prenatal testing, array comparative genomic hybridization, karyotype in amniotic fluid cells, karyotype in peripheral blood, and uniparental disomy analysis) revealed the fetal chromosomal status and indicated etiology giving rise to the mosaicism, suggesting a prezygotic meiotic error corrected through late trisomic rescue in the zygote.
染色体嵌合体是指在一个生物体中存在两种或更多源自同一胚胎的不同细胞系。5号染色体三体是常染色体三体最严重的形式之一，迄今为止仅报道过7例5号染色体嵌合三体病例。产前水平的嵌合体在遗传咨询中构成挑战，尤其是5号染色体嵌合三体的情况，因为其发病率较低。我们报告了一例产前诊断为5号染色体嵌合三体的女孩病例。产前和产后的基因检测（无创产前检测、阵列比较基因组杂交、羊水细胞核型分析、外周血核型分析和单亲二体分析）揭示了胎儿的染色体状况，并指出了导致嵌合体的病因，提示这是一个通过合子后期三体挽救得以纠正的合子前减数分裂错误。
