Unclassifiable pattern of hypopigmentation in a patient with mosaic partial 12p tetrasomy without Pallister-Killian syndrome
Unclassifiable pattern of hypopigmentation in a patient with mosaic partial 12p tetrasomy without Pallister-Killian syndrome
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DOI：
10.1002/ajmg.a.38269
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发表时间：
2017-07-01
影响因子：
2
通讯作者：
Dallapiccola, Bruno
中科院分区：
文献类型：
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作者：
Alesi, Viola;Dentici, Maria L.;Dallapiccola, Bruno
Pallister-Killian综合征（PKS-#OMIM601803）是一种多系统发育障碍，通常是由于非整倍体细胞系的存在，包括来自12号染色体短臂（12p同染色体）的多余四染色体标记（SCM）。临床表型与非整倍体细胞的百分比和组织分布密切相关，其特征为颅面畸形、色素皮肤异常、肢体缩短、先天性心脏缺陷、膈疝、张力低下、智力残疾和癫痫。我们报告一例4岁女孩携带12p部分同染色体，涉及PKS关键区域，影响约70%的循环淋巴细胞、尿液、唾液细胞和来自色素沉着的皮肤斑点的成纤维细胞，100%来自色素沉着的皮肤斑点的成纤维细胞。有趣的是，尽管受影响的细胞比例很高，但该患者并未出现PKS，唯一的临床表现是线状和斑片状色素嵌合。目前的观察结果表明，部分12p SCM也可能导致轻度表型，其在人群中的患病率可能被低估了。准确的皮肤病学评估可能是基因检测的主要手段。
Pallister-Killian syndrome (PKS-#OMIM601803) is a multisystem developmental disorder typically due to the presence of an aneuploidy cell line, consisting of a supernumerary tetrasomic chromosomal marker (SCM) arisen from the short arm of chromosome 12 (12p isochromosome). The clinical phenotype, which is strictly related to the percentage and tissue distribution of aneuploid cells, is characterized by craniofacial dysmorphisms, pigmentary skin anomalies, limb shortening, congenital heart defects, diaphragmatic hernia, hypotonia, intellectual disability, and epilepsy. We report on a 4 year-old girl harboring a 12p partial isochromosome, involving the PKS critical region, affecting about 70% of circulating lymphocytes, urine, and saliva cells and fibroblast from a hyperpigmented skin spot, and 100% of fibroblasts from a hypopigmented skin spot. Interestingly, despite the high proportion of affected cells this patient did not present with PKS, and a pattern of linear and patchy pigmentary mosaicism was the sole clinical manifestation. The present observation suggests that partial 12p SCM can also result in mild phenotypes, and its prevalence in the human population could have been underestimated. Accurate dermatologic evaluation could be a major handle for genetic testing.