Kagami–Ogata syndrome (KOS14) is a rare imprinting disorder characterized by a unique constellation of phenotypes including bell-shaped small thorax with coat-hanger appearance of the ribs. We encountered an African American female infant with KOS14 phenotype and 46,XX,t(2;14)(q11.2;q32.2)mat. After excluding upd(14)pat and an epimutation (hypermethylation) and a deletion affecting the maternally derived 14q32.2 imprinted region, we performed whole-genome sequencing, revealing that the translocation was generated between noncoding region at 2q11.2 and intron 6 of MEG3 at 14q32.2. Subsequent Sanger sequencing for the fusion points showed that the chromosomal fusion on the der(2) chromosome occurred between Chr2:102,193,994 (bp) and Chr14:101,314,628 (bp) in association with an insertion of 5-bp segment of unknown origin and that on the der(14) chromosome took place between Chr14:101,314,627 (bp) and Chr2:102,193,995 (bp) in association with an insertion of 1-bp segment of unknown origin (according to GRCh37/hg19). The results, together with the previous data in patients with KOS14, imply that the MEG3 disruption by 46,XX,t(2;14)(q11.2;q32.2)mat caused silencing of all MEGs including RTL1as and resultant excessive RTL1 expression, leading to the development of KOS14. To our knowledge, while Robertsonian translocations involving chromosome 14 have been reported in KOS14, this is the first case of KOS14 caused by a chromosomal translocation involving the 14q32.2 imprinted region.

Kagami-Ogata 综合征 (KOS14) 是一种罕见的印记疾病，其特征是具有独特的表型星座，包括钟形小胸，肋骨呈衣架状。我们遇到了一个具有 KOS14 表型和 46,XX, t (2;14)(q11.2;q32.2)mat 的非洲裔美国女婴。在排除 upd(14)pat 和表观突变（超甲基化）和影响母系衍生的 14q32.2 印记区域的缺失后，我们进行了全基因组测序，发现易位是在 2q11.2 的非编码区域和内含子 6 之间产生的。MEG3在 14q32.2。随后对融合点进行的 Sanger 测序表明，der(2) 染色体上的染色体融合发生在 Chr2:102,193,994 (bp) 和 Chr14:101,314,628 (bp) 之间，并伴有未知来源的 5-bp 片段的插入，以及der(14) 染色体发生在 Chr14:101,314,627 (bp) 和 Chr2:102,193,995 (bp) 之间，并伴有未知来源的 1-bp 片段的插入（根据 GRCh37/hg19）。结果，连同先前在 KOS14 患者中的数据，暗示MEG3被 46,XX, t (2;14)(q11.2;q32.2)mat 破坏导致所有MEG沉默，包括RTL1as和由此产生的过度RTL1表达，导致 KOS14 的发展。据我们所知，虽然在 KOS14 中已经报道了涉及 14 号染色体的罗伯逊易位，但这是第一个由涉及 14q32.2 印迹区域的染色体易位引起的 KOS14 病例。