Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
Dermatol Online J. 2024 Jul 15;30(3). doi: 10.5070/D330363866.
Tetrasomy 9p is a rare genetic syndrome resulting from two additional copies of the short arm of chromosome 9. Symptoms often present in the form of congenital abnormalities including cognitive disabilities, growth retardation, abnormal earlobes, congenital heart disease, and dysmorphia of the skull and face. Current literature suggests patients with tetrasomy 9p may exhibit any combination of these symptoms or, in rare instances, none at all. Although karyotyping, chromosomal microarray, and galactose-1-phosphate uridyltransferase activity analyses are the definitive diagnostic methods used, there remains a need for more robust clinical recognition in cases of mild phenotypic expression. Herein, we present a rare case of mosaic tetrasomy 9p in a long-term survival patient with multiple and recurrent pilomatrixomas, rare benign growths more commonly found in individuals under the age of 20. To our knowledge, only two previous reports have noted concurrent tetrasomy 9p with pilomatrixomas. We are the first to identify this phenotype in an adult tetrasomy 9p patient. Dermatopathology evaluation was conducted to verify our diagnoses. Our aim is to present a unique, additional case suggesting multiple pilomatrixomas as a new defining clinical presentation of mosaic tetrasomy 9p and to review the literature underlying the genetic changes associated with this syndrome.
9p 三体综合征是一种罕见的遗传综合征，由 9 号染色体短臂的两个额外拷贝引起。症状通常表现为先天性异常，包括认知障碍、生长迟缓、耳垂异常、先天性心脏病和颅骨和面畸形。目前的文献表明，9p 三体综合征患者可能表现出这些症状的任意组合，或者在极少数情况下，根本没有任何症状。虽然核型分析、染色体微阵列和半乳糖-1-磷酸尿苷酰转移酶活性分析是明确的诊断方法，但在轻度表型表达的情况下，仍需要更强大的临床识别。在此，我们报告了一例罕见的镶嵌型 9p 三体综合征长期存活患者，该患者患有多发性和复发性毛母细胞瘤，这是一种罕见的良性肿瘤，更常见于 20 岁以下的个体。据我们所知，仅有两份之前的报告指出 9p 三体综合征与毛母细胞瘤并存。我们是第一个在成年 9p 三体综合征患者中发现这种表型的人。进行了皮肤病理评估以验证我们的诊断。我们的目的是提出一个独特的、额外的病例，表明多发性毛母细胞瘤是镶嵌型 9p 三体综合征的新的明确临床表现，并回顾与该综合征相关的遗传变化的文献。
