Background: Chromosomal deletion involving the 6p25 region results in a clinically recognizable syndrome characterized by anterior eye chamber anomalies with risk of glaucoma and non-ocular malformations (6p25 deletion syndrome). We report a newborn infant case of childhood glaucoma with a combination of partial monosomy 6p25 and partial trisomy 18p11 due to an unbalanced translocation.

Materials and methods: The patient was a 0-year-old girl. Both eyes showed aniridia and left eye Peters anomaly with multiple malformations. To identify the chromosomal aberrations in the patient with clinically suspected 6p25 deletion syndrome, we performed cytogenetic analysis (G-banding and multicolor fluorescent in-situ hybridization) and array-based comparative genomic hybridization (array-CGH) analysis.

Results: Cytogenetic analyses revealed a derivative chromosome 6 with its distal short arm replaced by an extra copy of the short arm of chromosome 18. Array-CGH analysis detected a 4.6-Mb deletion at 6pter to 6p25.1 and 8.9-Mb duplication at 18pter to 18p11.22. To determine the breakpoint of the unbalanced rearrangement at the single-base level, we performed a long-range PCR for amplifying the junctional fragment of the translocation breakpoint. By sequencing the junctional fragment, we defined the unbalanced translocation as g.chr6:pter_4594783delinschr18:pter_8911541.

Conclusions: A phenotype corresponding to combined monosomy 6p25 and trisomy 18p11 presented as childhood glaucoma associated with non-acquired (congenital) ocular anomalies consist of aniridia and Peters anomaly and other systemic malformations. To the best of our knowledge, this is the first report which demonstrated the breakpoint sequence of an unbalanced translocation in a Japanese infant with childhood glaucoma.

背景：涉及6p25区域的染色体缺失会导致临床上可识别的综合征，其特征在于前眼房畸形具有青光眼和非眼畸形的风险（6p25缺失综合征）。我们报告了由于不平衡易位而合并的部分青光眼6p25和部分青光眼18p11的儿童青光眼的新生儿病例。

材料和方法：该患者为0岁女孩。两只眼睛都显示出虹膜异常和左眼Peters异常，并伴有多种畸形。为了鉴定临床怀疑为6p25缺失综合征的患者的染色体畸变，我们进行了细胞遗传学分析（G谱带和多色荧光原位杂交）和基于阵列的比较基因组杂交（array-CGH）分析。

结果：细胞遗传学分析显示，衍生的第6号染色体的远端短臂被多余的第18号染色体的短臂代替。阵列CGH分析检测到6pter至6p25.1处有4.6-Mb缺失，而18pter处有8.9-Mb复制。至18p11.22。为了确定单碱基水平上不平衡重排的断裂点，我们进行了长距离PCR，以扩增易位断裂点的连接片段。通过对连接片段进行测序，我们将不平衡易位定义为g.chr6：pter_4594783delinschr18：pter_8911541。

结论：表现为儿童青光眼并伴有非获得性（先天性）眼部异常的表型分别为6p25和三体性18p11组合，表现为虹膜异常和Peters异常以及其他系统性畸形。据我们所知，这是第一份报道，证明了日本青光眼婴儿的不平衡易位的断点序列。