Trisomy 14 is incompatible with live, but there are several patients reported with mosaic trisomy 14. We aimed to study the pattern of X inactivation and its effect on a translocated autosome and to find out an explanation of the involvement of chromosome 14 in 2 different structural chromosomal abnormalities. We report on a girl with frontal bossing, hypertelorism, low-set ears, micrognathia, cleft palate, congenital heart disease, and abnormal skin pigmentations. The patient displayed iris, choroidal, and retinal coloboma and agenesis of the corpus callosum and cerebellar vermis hypoplasia. Cytogenetic analysis revealed a karyotype 45,X,der(X)t(X;14)(q24;q11)[85]/46,XX,rob(14;14)(q10;q10),+14[35]. Array-CGH for blood and buccal mucosa showed high mosaic trisomy 14 and an Xq deletion. MLPA detected trisomy 14 in blood and buccal mucosa and also showed normal methylation of the imprinting center. FISH analysis confirmed the cell line with trisomy 14 (30%) and demonstrated the mosaic deletion of the Xq subtelomere in both tissues. There was 100% skewed X inactivation for the t(X;14). SNP analysis of the patient showed no region of loss of heterozygosity on chromosome 14. Also, genotype call analysis of the patient and her parents showed heterozygous alleles of chromosome 14 with no evidence of uniparental disomy. Our patient had a severe form of mosaic trisomy 14. We suggest that this cytogenetic unique finding that involved 2 cell lines with structural abnormalities of chromosome 14 occurred in an early postzygotic division. These 2 events may have happened separately or maybe there is a kind of trisomy or monosomy rescue due to dynamic cytogenetic interaction between different cell lines to compensate for gene dosage.

中文翻译：

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具有倾斜 X 失活的 14 三体和 t(X;14) 的两个异常细胞系

14 三体与活体不相容，但有几位患者报告了镶嵌 14 三体。我们旨在研究 X 失活的模式及其对易位常染色体的影响，并找出 14 号染色体参与 2 个不同结构的解释染色体异常。我们报告了一个女孩的额叶隆起、眼距过长、耳朵低位、小颌畸形、腭裂、先天性心脏病和异常皮肤色素沉着。患者出现虹膜、脉络膜和视网膜缺损以及胼胝体发育不全和小脑蚓部发育不全。细胞遗传学分析显示核型为 45,X,der(X)t(X;14)(q24;q11)[85]/46,XX,rob(14;14)(q10;q10),+14[35]。血液和口腔黏膜的 Array-CGH 显示高嵌合体 14 三体和 Xq 缺失。MLPA 在血液和口腔黏膜中检测到 14 三体，并且还显示印记中心的正常甲基化。FISH 分析证实了具有 14 三体 (30%) 的细胞系，并证明了两种组织中 Xq 亚端粒的镶嵌缺失。对于 t(X;14)，存在 100% 的倾斜 X 失活。患者的 SNP 分析显示 14 号染色体上没有杂合性缺失区域。此外，患者及其父母的基因型调用分析显示 14 号染色体的杂合等位基因，没有单亲二体的证据。我们的患者患有严重的嵌合体 14 三体。我们认为，这一细胞遗传学独特发现涉及 2 个具有 14 号染色体结构异常的细胞系，发生在早期的合子后分裂中。