BACKGROUND Pallister-Killian syndrome (PKS) is a rare disorder caused by the mosaic tetrasomy of chromosome 12p, and is characterized by facial dysmorphism, developmental delay, hypotonia and seizures. RESULTS We report a patient with PKS showing unique polymicrogyria with calcification. He had delayed development and dysmorphic facial features including frontal bossing, hypertelorism, and high arched palate at 6 months of age. Neuroimaging revealed unilateral polymicrogyria with spot calcifications, which predominantly affected the right perisylvian region. Chromosome G-banding showed the karyotype 46,XY, however, array-based comparative genomic hybridization analysis showed mosaic duplication of chromosome 12p, in which CCND2, which encodes cyclin D2 and is a downstream mediator of PI3K-AKT pathway, is located. Supernumerary chromosome of 12p was detected in 58% of buccal mucosa cells by the interphase fluorescence in situ hybridization analysis using chromosome 12 centromere-specific D12Z3 probe. The diagnosis of PKS was made based on distinctive clinical features of our patient and the results of cytogenetic analyses. CONCLUSION This report is, to our knowledge, the first case of a patient with PKS who clearly demonstrates polymicrogyria colocalized with calcifications, as shown by CT scans and MRI, and suggests that a patient with PKS could show structural brain anomalies with calcification. We assume that somatic mosaicism of tetrasomy could cause asymmetrical polymicrogyria in our patient, and speculate that increased dosages of CCND2 at chromosome 12p might be involved in the abnormal neuronal migration in PKS.

中文翻译：

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微阵列分析检测到 Pallister-Killian 综合征伴钙化的多小脑回

背景 Pallister-Killian 综合征 (PKS) 是一种由 12p 染色体镶嵌四体引起的罕见疾病，其特征是面部畸形、发育迟缓、肌张力减退和癫痫发作。结果 我们报告了一名 PKS 患者，显示出独特的多小脑回并伴有钙化。他在 6 个月大时出现了发育迟缓和畸形的面部特征，包括额部隆起、眼距过宽和上颚高拱。神经影像学显示单侧多小脑回伴点状钙化，主要影响右侧侧裂区。染色体 G 显带显示核型 46,XY，然而，基于阵列的比较基因组杂交分析显示染色体 12p 的镶嵌重复，其中 CCND2 编码细胞周期蛋白 D2，是 PI3K-AKT 通路的下游介质。通过使用染色体12着丝粒特异性D12Z3探针的间期荧光原位杂交分析，在58%的颊粘膜细胞中检测到12p的多余染色体。PKS 的诊断是基于我们患者独特的临床特征和细胞遗传学分析的结果。结论 据我们所知，本报告是第一例 PKS 患者，其明确表现出与钙化共存的多小脑回，如 CT 扫描和 MRI 所示，并表明 PKS 患者可能显示出伴有钙化的结构性脑异常。我们假设四体的体细胞嵌合可能导致我们患者的不对称多小脑回，并推测染色体 12p 处 CCND2 剂量的增加可能与 PKS 中的异常神经元迁移有关。